Hydrogeologic Framework of the Yakima River Basin 

Aquifer System, Washington

Scientific Investigations Report 2009–5152

Prepared in cooperation with the 

Bureau of Reclamation, 

Washington State Department of Ecology, and the 

Yakama Nation

U.S. Department of the Interior

U.S. Geological Survey
Cover: Photograph of Clark Well No. 1, located on the north side of the Moxee Valley in North Yakima, 

Washington. The well is located in township 12 north, range 20 east, section 6. The wall was drilled to 

a depth of 940 feet into an artesian zone of the Ellensburg Formation, and completed in 1897 at a cost of 

$2,000. The original flow from the well was estimated at about 600 gallons per minute, and was used to 

irrigate 250 acres in 1900 and supplied water to 8 small ranches with an additional 47 acres of irrigation. 

(Photograph was taken by E.E. James in 1897, and was printed in 1901 in the U.S. Geological Survey 

Water-Supply and Irrigation Paper 55.)
Hydrogeologic Framework of the Yakima 

River Basin Aquifer System, Washington

By J.J. Vaccaro, M.A. Jones, D.M. Ely, M.E. Keys, T.D. Olsen, W.B. Welch, and 

S.E. Cox

Prepared in cooperation with the Bureau of Reclamation, Washington State 

Department of Ecology, and the Yakama Nation

Scientific Investigations Report 2009–5152

U.S. Department of the Interior

U.S. Geological Survey
U.S. Department of the Interior

KEN SALAZAR, Secretary

U.S. Geological Survey

Suzette M. Kimball, Acting Director

U.S. Geological Survey, Reston, Virginia: 2009

For more information on the USGS—the Federal source for science about the Earth, its natural and living resources, 

natural hazards, and the environment, visit http://www.usgs.gov or call 1-888-ASK-USGS

For an overview of USGS information products, including maps, imagery, and publications, 

visit http://www.usgs.gov/pubprod

To order this and other USGS information products, visit http://store.usgs.gov

Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the 

U.S. Government.

Although this report is in the public domain, permission must be secured from the individual copyright owners to 

reproduce any copyrighted materials contained within this report.

Suggested citation:

Vaccaro, J.J., Jones, M.A., Ely, D.M., Keys, M.E., Olsen, T.D., Welch, W.B., and Cox, S.E., 2009, Hydrogeologic 

framework of the Yakima River basin aquifer system, Washington: U.S. Geological Survey Scientific Investigations 

Report 2009–5152, 106 p.
iii

Contents

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

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

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

Description of Study Area ............................................................................................................................4

Location and Setting ............................................................................................................................4

Development of Water Resources.....................................................................................................4

Overview of the Geology......................................................................................................................7

Well Information...........................................................................................................................................10

References to Wells ...........................................................................................................................10

Well Data and Their Use....................................................................................................................10

Hydrogeologic Units....................................................................................................................................10

Hydraulic Characteristics of Units............................................................................................................20

Lateral Hydraulic Conductivity .........................................................................................................20

Basin-Fill Units............................................................................................................................20

Columbia River Basalt Group Units.........................................................................................20

Bedrock Units.............................................................................................................................25

Estimates from Specific-Capacity Data .................................................................................25

Estimates from Aquifer Tests ...................................................................................................28

Vertical Hydraulic Conductivity ........................................................................................................28

Basin-Fill Units............................................................................................................................28

Columbia River Basalt Group Units.........................................................................................29

Bedrock Units.............................................................................................................................29

Storage Coefficient.............................................................................................................................29

Hydrochemistry............................................................................................................................................30

Variation in Major-Ion Concentration..............................................................................................31

Deuterium and Oxygen-18.................................................................................................................31

Methane ...............................................................................................................................................33

Carbon and Tritium Isotopes .............................................................................................................33

Noble Gases.........................................................................................................................................37

Groundwater in the Yakima River Basin ..................................................................................................38

Occurrence..........................................................................................................................................38

Conditions of Occurrence .................................................................................................................43

Flow System.........................................................................................................................................53

Groundwater Use.........................................................................................................................................59

Water-Level Trends .....................................................................................................................................64

Water Budget for the Yakima River Basin ...............................................................................................79

Summary and Conclusions.........................................................................................................................80

Acknowledgments.......................................................................................................................................81

Selected References...................................................................................................................................82
iv

Contents—Continued

Plates

[in pocket]

Plate 1. Maps showing location of six structural basins and extents of basin-fill 

hydrogeologic units, Yakima River basin aquifer system, Washington. 

Plate 2. Maps showing surficial extent of bedrock hydrogeologic units, and extent and 

altitude of the top of the Columbia River Basalt Group hydrogeologic units, 

Yakima River basin aquifer system, Washington.

Plate 3. Map showing generalized altitude of the water-table in six structural basins, 

spring 2001, Yakima River basin aquifer system, Washington. 

Plate 4. Maps showing generalized altitude of groundwater levels for the Saddle 

Mountains, Wanapum, and Grande Ronde units, approximating spring 2001 

conditions, Yakima River basin aquifer system, Washington.

Appendix A. Methods and Assumptions Used to Estimate Lateral Hydraulic 

Conductivity from Specific-Capacity Data.................................................................................91

Appendix B. Hydrochemical Data from Groundwater Samples, Yakima River Basin 

Aquifer System, Washington........................................................................................................92

Appendix C. Methods Used to Estimate Groundwater Recharge for the Area Outside

the Yakima River Basin in the Extended Study Area ..............................................................102

Appendix D. Estimation of Mean Annual Values and Development of Time-Series of 

Monthly Values for Surface-Water Diversions, Yakima River Basin, Washington ...........105

Figures

Figure 1. Map showing Yakima River basin, Washington.......................................... 3

Figure 2. Map showing land use and land cover, Yakima River basin, Washington, 1999 ... 5

Figure 3. Selected tributaries, diversion canals, return flows, and streamflow-gaging

stations, Yakima River basin, Washington................................................ 6

Figure 4. Map showing distribution of depths of water wells, Yakima River basin, 

Washington ................................................................................. 8

Figure 5. Map showing simplified surficial geology, Yakima River basin, Washington......... 9

Figure 6. Map showing location of wells with water-level measurements, June 2000

through June 2002, Yakima River basin, Washington ................................. 11

Figure 7. Map showing location of six structural basins and geologic structure, Yakima

River basin aquifer system, Washington ................................................ 16

Figure 8. Map showing extent of surficial hydrogeologic units, Yakima River basin

aquifer system, Washington ............................................................... 19

Figure 9. Map showing reported yields of wells, Yakima River basin aquifer system,

Washington ................................................................................. 26
v

Figures—Continued

Figure 10. Graph showing frequency distribution of lateral hydraulic conductivity values

estimated from specific-capacity data, Yakima River basin aquifer system,

Washington ................................................................................. 27

Figure 11. Box plots showing distribution of lateral hydraulic conductivity estimated from

aquifer test data, Yakima River basin aquifer system, Washington .................. 28

Figure 12. Graph showing relation between stable isotopic composition (deuterium and

oxygen-18) samples in all water samples, precipitation in the Toppenish basin,

surface water in the Yakima River basin, and groundwater in the Toppenish

basin, Washington........................................................................... 32

Figure 13. Map showing the spatial distribution of dissolved methane concentrations and

carbon-13 ratios of dissolved methane in groundwater, Yakima River basin

aquifer system, Washington ............................................................... 34

Figure 14. Graphs showing relation between tritium and δ13C and carbon-14 (14C)

concentrations in dissolved inorganic carbon of groundwater samples from

the Toppenish and Yakima basins, Washington and δ13C and fluoride and

chloride concentrations .................................................................. 35

Figure 15. Graph showing concentrations of noble gases in groundwater samples from

Yakima River basin aquifer system, Washington, and calculated

concentrations of noble gases in air-saturated water ................................. 37

Figure 16. Map showing spatial distribution of mean annual recharge for current

conditions, 1960–2001, Yakima River basin aquifer system, Washington ............ 40

Figure 17. Map showing surface-water irrigation districts, Yakima River basin, Washington 41

Figure 18. Map showing generalized depth to water table for parts of the Yakima River

basin aquifer system, Washington ...................................................... 44

Figure 19. Hydrographs showing depth-to-water in four wells, Yakima River basin,

Washington ................................................................................. 46

Figure 20. Maps showing location and depth of historical and present-day flowing wells,

and location of historical and present-day springs, Yakima River basin aquifer

system, Washington ........................................................................ 49

Figure 21. Hydrographs showing depth-to-water in wells completed in the Wanapum

unit, and wells completed in the Wanapum 12N/21E-16L01) and Saddle

Mountains (12N21E-16N02) units, Yakima River basin aquifer system, Washington 51

Figure 22. Map showing spatial distribution of pumpage from the Yakima River basin

aquifer system, Washington, 2001......................................................... 62

Figure 23. Map showing spatial distribution of cumulative pumpage from the Yakima

River basin aquifer system, Washington, 1960–2001 .................................... 63

Figure 24. Map showing location and estimated mean annual quantity of surface-water

diversions in the Yakima River basin, Washington .................................... 64

Figure 25. Graphs showing examples of groundwater level hydrographs with stable or

small declines, Yakima River basin, Washington ....................................... 66

Figure 26. Graphs showing examples of groundwater level hydrographs with moderate

declines, Yakima River basin, Washington ............................................. 67

Figure 27. Graphs showing examples of groundwater level hydrographs with large

declines, Yakima River basin, Washington ............................................. 68
vi

Figures—Continued

Figure 28. Graphs showing examples of groundwater level hydrographs with very large

declines, Yakima River basin, Washington ............................................. 70

Figure 29. Map showing location of irrigation wells completed in the basin-fill deposits,

Yakima River basin aquifer system, Washington ....................................... 72

Figure 30. Map showing generalized trends in groundwater levels, Saddle Mountains

unit, Yakima River basin aquifer system, Washington ................................. 74

Figure 31. Map showing generalized trends in groundwater levels, Wanapum unit,

Yakima River basin aquifer system, Washington ....................................... 75

Figure 32. Map showing generalized trends in groundwater levels, Grande Ronde unit,

Yakima River basin aquifer system, Washington ....................................... 76

Figure 33. Map showing spatial distribution of cumulative groundwater recharge for

1960–2001, Yakima River basin aquifer system, Washington........................... 77

Figure 34. Map showing spatial distribution of the difference between groundwater

recharge and pumpage acummulated for 1960–2001 for areas with pumpage,

Yakima River basin aquifer system, Washington ....................................... 78

Tables

Table 1. Information for the hydrogeologic units of the Yakima River basin aquifer

system, Washington ........................................................................ 12

Table 2. Correlation chart showing the regional relation between generalized geologic

and hydrogeologic units in the basin-fill and Columbia River Basalt Group

units, and bedrock units for the Yakima River basin aquifer system, Washington... 14

Table 3. Summary of previous estimates of lateral hydraulic conductivity, Yakima River

basin aquifer system, Washington ...................................................... 21

Table 4. Summary of lateral hydraulic conductivity values, estimated from

specific-capacity data, Yakima River basin aquifer system, Washington ............ 27

Table 5. Summary of estimated annual pumpage, by pumpage category in 5-year

increments, Yakima River basin, Washington, 1960–2000 .............................. 60

Table 6. Generalized mean annual water budget for the Yakima River basin, 

Washington ................................................................................. 79
vii

Conversion Factors, Datums, and Abbreviations and 

Acronyms 

Conversion Factors

Multiply By To obtain

Length

inch (in.) 2.54 centimeter (cm)

inch (in.) 25.4 millimeter (mm)

foot (ft) 0.3048 meter (m)

mile (mi) 1.609 kilometer (km)

Area

acre 4,047 square meter (m2)

acre 0.004047 square kilometer (km2)

section (640 acres or 1 square mile) 259.0 square hectometer (hm2) 

square mile (mi2) 2.590 square kilometer (km2) 

Volume

cubic inch (in3) 16.39 cubic centimeter (cm3) 

acre-foot (acre-ft) 1,233 cubic meter (m3)

Flow rate

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

cubic foot per second (ft3/s) 0.02832 cubic meter per second (m3/s)

cubic foot per second per square mile 

[(ft3/s)/mi2]

 0.01093 cubic meter per second per square 

kilometer [(m3/s)/km2]

cubic foot per day (ft3/d) 0.02832 cubic meter per day (m3/d)

gallon per minute (gal/min) 0.06309 liter per second (L/s)

inch per year (in/yr) 25.4 millimeter per year (mm/yr)

Pressure

pound per square foot (lb/ft2) 0.04788 kilopascal (kPa)

Specific capacity

gallon per minute per foot 

[(gal/min)/ft)] 0.2070 liter per second per meter [(L/s)/m]

Hydraulic conductivity

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

Hydraulic gradient

foot per mile (ft/mi) 0.1894 meter per kilometer (m/km)

Transmissivity*

foot squared per day (ft2/d) 0.09290 meter squared per day (m2/d) 

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

°F=(1.8×°C)+32.

*Transmissivity: The standard unit for transmissivity is cubic foot per day per square foot times 

foot of aquifer thickness [(ft3/d)/ft2]ft. In this report, the mathematically reduced form, foot 

squared per day (ft2/d), is used for convenience.

Specific conductance is given in microsiemens per centimeter at 25 degrees Celsius (μS/cm at 

25°C).

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

or micrograms per liter (μg/L).
viii

Datums

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

(NAVD 88).

Horizontal coordinate information is referenced, unless otherwise noted, to the North American 

Datum of 1983 (NAD 83).

Altitude, as used in this report, refers to distance above the vertical datum.

Abbreviations and Acronyms

CID Cascade Irrigation District

CO2 carbon dioxide

CRBG Columbia River Basalt Group

DIC dissolved inorganic carbon

DPM Deep Percolation Model

DTW depth to water table

GMWL Global Meteoric Water Line

He helium

Kh lateral hydraulic conductivity

Kv vertical hydraulic conductivity

MAP mean annual precipitation

NWIS National Water Inventory System

PMC percent modern carbon

Reclamation Bureau of Reclamation

STP standard temperature and pressure

TWSA total water supply available

USGS U.S. Geological Survey

WaDOE Washington State Department of Ecology

WIP Wapato Irrigation Project

YN Yakama Nation

Conversion Factors, Datums, and Abbreviations and 

Acronyms—Continued
ix

Well Numbering System

The USGS assigns numbers to wells and springs in Washington that identify their locations in a 

township, range, and section. Well number 20N/15E-26N01 indicates, successively, the township 

(T.20 N.) and the range (R.15 E.) north and east of the Willamette baseline and meridian. The 

first number following the hyphen indicates the section (26) within the township and the letter 

following the section number (N) gives the 40-acre subdivision within the section. The number 

(01) following the letter is the sequence number of the well within the 40-acre subdivision. An 

‘S’ following the sequence number indicates that the site is a spring, a ‘D1’ after the sequence 

number indicates that the original reported depth of the well has been changed once and 

successive numbers indicate the number of changes in the well depth. An ‘R’ following the 

sequence number indicates the well has been reconditioned. A ‘P1’ or an ‘A’ after the sequence 

number indicates a group of nested piezometers, with successive numbers or letters assigned 

to each piezometer in the group.

Willamette

Meridian

Willamette Base Line

SECTION 26 

20N/15E-26N01 

ABCD

E F G H

JKLM

N P Q R

R. 15 E. 

T. 

20 

 N. 

1 2 3 4 5 6 

7 12 

18 13 

19 24 

30 25 26 

31 32 33 34 35 36 

W A S H I N G T O N 

Yakima River Basin

Diagram of well numbering system in the State of Washington.
x

This page intentionally left blank.
Hydrogeologic Framework of the Yakima River Basin 

Aquifer System, Washington

By J.J. Vaccaro, M.A. Jones, D.M. Ely, M.E. Keys, T.D. Olsen, W.B. Welch, and S.E. Cox

Abstract

The Yakima River basin aquifer system underlies 

about 6,200 square miles in south-central Washington. The 

aquifer system consists of basin-fill deposits occurring in six 

structural-sedimentary basins, the Columbia River Basalt 

Group (CRBG), and generally older bedrock. The basin-fill 

deposits were divided into 19 hydrogeologic units, the CRBG 

was divided into three units separated by two interbed units, 

and the bedrock was divided into four units (the Paleozoic, 

the Mesozoic, the Tertiary, and the Quaternary bedrock units). 

The thickness of the basin-fill units and the depth to the top 

of each unit and interbed of the CRBG were mapped. Only 

the surficial extent of the bedrock units was mapped due to 

insufficient data. Average mapped thickness of the different 

units ranged from 10 to 600 feet.

Lateral hydraulic conductivity (Kh) of the units varies 

widely indicating the heterogeneity of the aquifer system. 

Average or effective Kh values of the water-producing zones 

of the basin-fill units are on the order of 1 to 800 ft/d and are 

about 1 to 10 ft/d for the CRBG units as a whole. Effective or 

average Kh values for the different rock types of the Paleozoic, 

Mesozoic, and Tertiary units appear to be about 0.0001 to 

3 ft/d. The more permeable Quaternary bedrock unit may have 

Kh values that range from 1 to 7,000 ft/d. Vertical hydraulic 

conductivity (Kv) of the units is largely unknown. Kv values 

have been estimated to range from about 0.009 to 2 ft/d for the 

basin-fill units and Kv values for the clay-to-shale parts of the 

units may be as small as 10-10 to 10-7 ft/d. Reported Kv values 

for the CRBG units ranged from 4×10-7 to 4 ft/d.

Variations in the concentrations of geochemical solutes 

and the concentrations and ratios of the isotopes of hydrogen, 

oxygen, and carbon in groundwater provided information on 

the hydrogeologic framework and groundwater movement. 

Stable isotope ratios of water (deuterium and oxygen-18) 

indicated dispersed sources of groundwater recharge to the 

CRBG and basin-fill units and that the source of surface and 

groundwater is derived from atmospheric precipitation. The 

concentrations of dissolved methane were larger than could 

be attributable to atmospheric sources in more than 80 percent 

of wells with measured methane concentrations. The 

concentrations of the stable isotope of carbon-13 of methane 

were indicative of a thermogenic source of methane. Most of 

the occurrences of methane were at locations several miles 

distant from mapped structural fault features, suggesting the 

upward vertical movement of thermogenic methane from the 

underlying bedrock may be more widespread than previously 

assumed or there may be a more general occurrence of 

unmapped (buried) fault structures. Carbon and tritium isotope 

data and the concentrations of dissolved constituents indicate a 

complex groundwater flow system with multiple contributing 

zones to groundwater wells and relative groundwater residence 

time on the order of a few tens to many thousands of years.

Potential mean annual recharge for water years 

1950–2003 was estimated to be about 15.6 in. or 7,149 ft3/s 

(5.2 million acre-ft) and includes affects of human activities 

such as irrigation of croplands. If there had been no human 

activities (predevelopment conditions) during that time 

period, estimated recharge would have been about 11.9 in. 

or 5,450 ft3/s (3.9 million acre-ft). Estimated mean annual 

recharge ranges from virtually zero in the dry parts of the 

lower basin to more than 100 in. in the humid uplands, where 

annual precipitation is more than 120 in.

Groundwater in the different hydrogeologic units occurs 

under perched, unconfined, semiconfined, and confined 

conditions. Groundwater moves from topographic highs in 

the uplands to topographic low areas along the streams. The 

flow system in the basin-fill units is compartmentalized due 

to topography and geologic structure. The flow system also 

is compartmentalized for the CRBG units but not to as large 

an extent as in the basin-fill units. Regional groundwater 

flow discharges to surface-water drainage features in the 

lowlands in the structural basins. The gradient of the water 

table ranges from about 7 ft/mi to more than 400 ft/mi, with 

the smaller gradients in the topographically smooth parts of 

the structural basins. Typically, hydraulic gradients are similar 

to the topographic gradients. The lateral hydraulic gradient 

in the CRBG units also is highly variable and ranges from 

about 3 to 14 ft/mi in the flatter parts of the structural basins 

to as much as 800 ft/mi in areas of steep terrain. The hydraulic 

gradient of the CRBG units generally is within 5 degrees of 

the topographic gradient.
2 Hydrogeologic Framework of the Yakima River Basin Aquifer System, Washington

About 312,000 acre-ft (about 430 ft3/s) of groundwater 

was pumped in 2000 for multiple uses, about 60 percent of 

which was for irrigation. Allowable acreage of groundwater 

irrigation rights is about 130,000 acres. Mean annual surfacewater diversions are about 5,800 ft3/s, of which about 

66 percent was delivered for irrigation and 25 percent was for 

power production.

Excluding the initial water-level rises due to surfacewater irrigation that started in the late 1800s, long-term 

measurements of the levels indicate they have been stable or 

have declined less than 20 ft in most of the aquifer system. 

Declines from 21 to 300 ft have occurred in some areas due to 

pumpage. The largest declines have been in the CRBG units. 

The pumpage from the basin-fill units, from which about 

50 percent of the pumpage occurs, appears to have caused 

declines in only two small areas, but the withdrawals may be 

reducing groundwater discharge.

Introduction

Surface water in the Yakima River basin, in southcentral Washington (fig. 1) is under adjudication. The amount 

of surface water available for appropriation is unknown, 

but there are increasing demands for water for municipal, 

fisheries, agricultural, industrial, and recreational uses. These 

demands must be met by groundwater withdrawals and (or) 

by changes in the way water resources are allocated and used. 

On-going activities in the basin for enhancement of fisheries 

and obtaining additional water for agriculture may be affected 

by groundwater withdrawals and by rules implemented under 

the Endangered Species Act for salmonids that have been 

either listed or were proposed for listing in the late 1990s. An 

integrated understanding of the groundwater flow system and 

its relation to the surface-water resources is needed in order 

to implement most water-resources management strategies 

in the basin. In order to gain this understanding, a study of 

the Yakima River basin aquifer system began in June 2000. 

The study is a cooperative effort of the U.S. Geological 

Survey (USGS), Bureau of Reclamation (Reclamation), the 

Washington State Department of Ecology (WaDOE), and the 

Yakama Nation (YN). 

The overall objectives of the study are to fully describe 

the groundwater flow system and its interaction with and 

relation to surface water, and to provide baseline information 

for a management tool—a numerical model of the system. 

The conceptual model of the flow system and the results of 

the study can be used to guide and support actions taken by 

management agencies with respect to groundwater availability 

and to provide information to other stakeholders and interested 

parties. The numerical model will be developed as an 

integrated tool to assess short-term to long-term management 

activities, including the testing of the potential effects of 

alternative management strategies for water development and 

use. 

The study includes three phases. The first phase includes 

(1) project planning and coordination, (2) compiling, 

documenting, and assessing available data, and (3) initial data 

collection. The second phase consists of data collection to 

support the following Phase 2 work elements: (1) mapping 

of hydrogeologic units, (2) estimating groundwater 

pumpage, (3) developing estimates of groundwater recharge, 

(4) assessing groundwater-surface water interchanges, and 

(5) constructing maps of groundwater levels. Together, these 

five elements provide the information needed to describe the 

groundwater flow system, develop the conceptual model, and 

provide the building blocks for the hydrogeologic framework. 

In the third phase, a regional-scale numerical model of the 

groundwater flow system will be constructed in order to 

integrate the available information. The numerical model 

will be used to enhance understanding of the flow system 

(including a water budget for the aquifer system) and its 

relation to surface water, and to test alternative management 

strategies.

The results of selected work elements of this study 

have been described in a series of reports (Jones and others, 

2006; Vaccaro and Maloy, 2006; Vaccaro and Sumioka, 

2006; Vaccaro, 2007; Vaccaro and Olsen, 2007a, b; Jones and 

Vaccaro, 2008; Keys and others, 2008; Vaccaro and others, 

2008). 

Purpose and Scope

This report presents the hydrogeologic framework of 

the Yakima River basin aquifer system, including a brief 

description of the hydrogeologic units composing the aquifer 

system and their characteristics, hydrochemistry, groundwater 

occurrence and conditions, movement of groundwater in the 

flow system, groundwater use, and the status and trends of 

groundwater levels. The information is described in terms of 

the characteristics of the hydrogeologic units that compose 

the aquifer system. This information was used to develop a 

generalized water budget for the Yakima River basin.
Purpose and Scope 3

wa19_0148_fig01-drainage

82

22

22

97

97

97

12

12

82

82

240

24

410

240

90

90

90

24

410

12

97

12

241

82

82 12

KITTITAS COUNTY

YAKIMA COUNTY

COUNTY

BENTON COUNTY

KLICKITAT

COUNTY

YAKIMA

EXPLANATION

Boundary of Yakima River Basin

Canal

Roza

Sunnyside Canal

Main Canal

Extension

Kennewick

Main Canal

Marion Drain

North

Branch

Canal

Kittitas Main Canal

Bumping

Lake N Fk

S Fk

S Fk

N Fk

S Fk

N Fk

N Fk

Cle Elum River

Swauk Creek

Caribou Cr

Coleman Cr

Naneum

Cr

Cooke Cr

Crow Creek

Bumping River

American River

Rattlesnake Cr

Little Rattlesnake Cr

Nile Creek

Manastash

Badger Creek

Lmuma Cr

Ahtanum Creek

Oak Creek

Tieton River

Wide Hollow Cr

Wenas Creek

Selah Creek

North Fork

Dry Creek

Simcoe Creek

Agency Creek

Creek

Toppenish

Corral Cr

RIVER

Spring Cr

Logy Creek

Satus

Creek

Mule Dry

Creek

Cle

Elum

Lake

Rimrock

Lake

Kachess Lake

Keechelus Lake

Lake

Wallula

Priest

Rapids

Lake

Teanaway River Reecer Cr

Wilson Creek

Park Cr

Taneum Creek

Umtanum Creek

Little Naches River

Cr

Cowiche Creek

Cowiche Creek

River

Naches

Snipes Cr

Sulphur Cr Wasteway

Cherry

Cr

S Fk

N Fk

YAKIMA

YAKIMA

RIVER

Cle Elum

Parker

Wapato

Ellensburg

Umtanum

Kittitas

Thrall

Toppenish

Moxee City Union Gap

Yakima

Selah

Naches

Sunnyside Richland

Kiona

Kennewick Prosser

Grandview

Mabton

Satus

Zillah

Granger

Roza

Easton

Teanaway

Tieton Rimrock

Snoqualmie

Pass

Van Epps

Pass

Esmeralda

Peaks

K I T T I T A S

V A L L E Y

M A N A S T A S H

KACHESS RIDGE

R I D G E

UNION GAP

CLEMAN

MOUNTAIN

TEANAWAY

NORTH RIDGE

U M T A N U M

R I D G E

Deception

Pass

Y A K I M A

 V A L L E Y

AHTANUM RIDGE

COWICHE MTN

AMERICAN RIDGE

CLE ELUM

RIDGE

RIDGE

TOPPENISH RIDGE

R A T T L E S N A K E H I L L S

Y A K I M A R I D G E

H O R S E

H E A V E N

H I L L S

C

A

S C A

D E R

A

N

G

E

W E N AT C H E E

M O U N TA I N S

Gilbert

Peak

121°

47°

47°

30'

46°

121°30' 120°30' 120° 119°30'

46°

30'

0 5 10 20 30 40 MILES

0 5 10 20 30 40 KILOMETERS

Yakima

River

Basin

WASHINGTON

 COLUMBIA

 RIVER

T.

24

N.

T.

22

N.

T.

20

N.

T.

18

N.

T.

16

N.

T.

14

N.

T.

12

N.

T.

10

N.

T.

8

N.

T.

6

N.

R.10E. R.12E. R.14E. R.16E. R.18E. R.20E. R.22E. R.24E. R.26E. R.28E.

Hanford Site

Base modified from U.S. Geological Survey data and other digital sources

Universal Transverse Mercator projection, Zone 10

Horizontal Datum: North American Datum of 1927 (NAD 27)

Figure 1. Yakima River basin, Washington.
4 Hydrogeologic Framework of the Yakima River Basin Aquifer System, Washington

Description of Study Area

The location and setting of the Yakima River basin, a 

summary of the development of water resources in the basin, 

and an overview of the geology are presented to provide a 

general background for understanding the study area.

Location and Setting

 The Yakima River basin encompasses about 6,200 mi2

in south-central Washington (fig. 1). The Yakima River basin 

produces a mean annual unregulated streamflow (adjusted 

for regulation and without diversions or returns) of about 

5,600 ft3/s (4.1 million acre-ft or about 0.9 (ft3/s)/mi2) and a 

regulated streamflow of about 3,600 ft3/s (2.6 million acre-ft 

or about 0.6 (ft3/s)/ mi2). The basin includes three Washington 

State Water Resource Inventory Areas (WRIA—numbers 

37, 38, and 39), part of the Yakama Nation lands, and three 

ecoregions (Cascades, Eastern Cascades, and Columbia 

Basin—Omernik, 1987; Cuffney and others, 1997). Almost all 

of Yakima County, more than 80 percent of Kittitas County, 

and about 50 percent of Benton County are in the basin. Less 

than 1 percent of the basin, principally in an unpopulated 

upland area, lies in Klickitat County. 

The headwaters of the basin are on the upper, humid 

eastern slope of the Cascade Range, where mean annual 

precipitation is more than 120 in. The basin terminates at 

the confluence of the Yakima and Columbia Rivers in the 

low-lying, arid part of the basin that receives about 6 in. of 

precipitation per year. Altitudes in the basin range from 400 ft 

to nearly 8,000 ft. Eight major rivers and numerous smaller 

streams are tributary to the Yakima River (fig. 1), the largest 

of which is the Naches River. Most of the precipitation in the 

basin falls during the winter months as snow in the mountains. 

The mean annual precipitation over the entire basin is about 

27 in. (about 12,300 ft3/s or 8.9 million acre-ft). The spatial 

pattern of mean annual precipitation resembles the pattern 

of the basin’s highly variable topography. The difference 

between the mean annual precipitation and mean annual 

unregulated streamflow is 6,700 ft3/s (about 4.8 million 

acre-ft). On the basis of this difference and the assumption of 

only small groundwater inflow to or outflow from the aquifer 

system, about 55 percent of the precipitation was lost to 

evapotranspiration under natural conditions.

The basin is separated into several broad valleys by eastwest trending anticlinal ridges. The valley floors slope gently 

toward the Yakima River. Few perennial tributary streams 

traverse these valleys. Most of the population and economic 

activity occurs in these valleys.

Irrigated agriculture is the principal economic activity 

in the basin. The average annual surface-water demand 

met by Reclamation’s Yakima Project is about 2.5 million 

acre-ft; an additional 336,000 acre-ft of demand in the lower 

part of the basin is separate from the demand met by the 

Project. Additional surface-water demand that is not met by 

Reclamation occurs in smaller tributaries and on the large 

rivers; this demand is based on State appropriated water. More 

than 95 percent of the surface-water demand is for irrigation 

of about 500,000 acres in the low-lying semiarid to arid parts 

of the basin (fig. 2). The demand is partly met by storage 

of nearly 1.1 million acre-ft of water in five Reclamation 

reservoirs. The major management point for Reclamation 

is the streamflow-gaging station at the Yakima River near 

Parker at river mile 103.7 (USGS station number 12505000, 

fig. 3); this site is just downstream of the Sunnyside and 

Wapato (main) canal diversions. Just upstream of this site at 

about river mile 106.9 is the location that is considered the 

dividing line between the upper (mean annual precipitation of 

7–145 in.) and lower (mean annual precipitation of 6–45 in.) 

parts of the Yakima River basin. About 45 percent of the 

water diverted for irrigation is eventually returned to the river 

system as surface-water inflows and groundwater discharge, 

but at varying time-lags (Bureau of Reclamation, 1999). 

During the low-flow period, these return flows, on average, 

account for about 75 percent of the streamflow downstream 

of the streamflow-gaging station near Parker. Most of the 

surface-water demand in the basin downstream of Parker 

is met by these return flows and not by the release of water 

from the reservoirs. As a result of water use in the basin, the 

difference between mean annual unregulated (5,600 ft3/s) 

and regulated (3,600 ft3/s) streamflow in the basin is about 

2,000 ft3/s, suggesting that some 1.4 million acre-ft of water, 

or about 17 percent of the precipitation in the basin, is 

consumptively used—principally by irrigated crops through 

evapotranspiration.

Development of Water Resources

Missionaries arrived in the basin in 1848 and established 

a mission in 1852 on Atanum (now Ahtanum) Creek. They 

were some of the first non-Indian settlers to use irrigation on 

a small scale. Miners and cattlemen immigrated to the basin 

in the 1850s and 1860s, which resulted in a new demand for 

water. With increased settlement in the mid-1860s, irrigation 

of the fertile valley bottoms began and the outlying areas were 

extensively used for raising stock. One of the first known 

non-Indian irrigation ditches was constructed in 1867 and 

diverted water from the Naches River (Parker and Storey, 

1916; Flaherty, 1975). Private companies later delivered 

water through canal systems built between 1880 and 1904 

for the irrigation of large areas. The development of irrigated 

agriculture was made more attractive by the construction 

of the Northern Pacific Railway that reached Yakima in 

December 1884 and provided a means to transport agricultural 

goods to markets; two years later, the completion of the 

railway to the Pacific coast provided new and easily accessible 
Description of Study Area 5

Figure 2. Land use and land cover, Yakima River basin, Washington, 1999.

wa19-0148_fig02_land cover

Richland

Yakima

EXPLANATION

Simplified land cover

Boundary of agricultural area

Forest (33 percent)

Range (36 percent)

Cities and towns (2 percent)

Agriculture (28 percent)

Hops

Irrigated hay

Mixed row crops

Orchards

Orchards and grapes

Undifferentated agriculture

Lakes and reservoirs (1 percent)

121°

47°

47°

30'

46°

121°30' 120°30' 120° 119°30'

46°

30'

KITTITAS COUNTY

YAKIMA COUNTY

COUNTY

BENTON COUNTY

KLICKITAT

COUNTY

YAKIMA

0 5 10 20 30 40 MILES

0 5 10 20 30 40 KILOMETERS

YAKIMA RIVER

 YAKIMA RIVER

T.

24

N.

T.

22

N.

T.

20

N.

T.

18

N.

T.

16

N.

T.

14

N.

T.

12

N.

T.

10

N.

T.

8

N.

T.

6

N.

R.10E. R.12E. R.14E. R.16E. R.18E. R.20E. R.22E. R.24E. R.26E. R.28E.

markets for agricultural products. The State of Washington 

was created in 1889, spurring further growth in the basin, 

especially because the cities of Ellensburg and Yakima were 

in contention for being the state capital. By 1902, about 

120,000 acres were under irrigation, mostly by surface water 

(Parker and Storey, 1916; Bureau of Reclamation, 1999).

The Federal Reclamation Act of 1902 enabled the 

construction of Federal water projects in the western 

United States in order to expand the development of the 

West. In 1905, the Washington State Legislature passed 

the Reclamation Enabling Act, and the Yakima Federal 

Reclamation Project was authorized to construct facilities to 
6 Hydrogeologic Framework of the Yakima River Basin Aquifer System, Washington

CITY OF YAKIMA 

RM 115.9 

RM 113.3 

RM 111.0 

RM 107.4 

RM 106.9 

RM 106.7 

RM 103.8 

RM 89.2 

RM 86.0 

RM 83.2 

RM 82.8 

RM 82.8 

RM 82.6 

RM 80.4 

RM 77.0 

RM 69.6 

RM 69.3 

RM 65.1 

RM 35.5 

RM 47.1 

RM 46.5 

RM 41.8 

RM 41.8 

RM 35.8 

RM 35.8 

RM 34.9 

RM 28.6 

RM 18.0 

Mouth of 

Yakima River 

RM 0.0 

RM 18.0 

RM 107.3 

12500450

RM 116.3 

RM 29.9 

12510500

RM 55.0 

12509050

RM 103.7 

12505000

RM 61.0 

COLUMBIA RIVER 

Kiona Canal

Benton City STP

Columbia Canal

Richland Canal

Corral Canyon Creek

Chandler Canal

Prosser STP

Spring Creek

Snipes Creek

Chandler Canal

Kennewick Canal

Satus Drain 303

Mabton STP

Continued at top of next column 

RM 203.5 

RM 202.5 

RM 183.1 

RM 179.6 

RM 176.1 

RM 173.9 

RM 169.9 

RM 166.1 

RM 166.1 

RM 161.3 

RM 160.3 

RM 156.3 

RM 154.5 

RM 151.5 

RM 147.0 

RM 139.8 

RM 127.9 

RM 123.7 

RM 123.6 

RM 122.4 

RM 117.0 

RM 185.6 

RM 202.0 

12477000

RM 214.4 

12474500

RM 182.9 

12479500

RM 140.4 

12484500

RM 16.8 

12494000

RM 12.6 

RM 9.7 

RM 9.7 

RM 8.5 

RM 3.6 

RM 17.5 

RM 17.1 

YAKIMA RIVER

Moxee Canal

Roza Power Plant Return Flow 

Yakima STP 

Wide Hollow Creek 

Moxee Drain 

Moxee City STP 

North Fork 

Ahtanum Creek Ahtanum Creek 

South Fork 

Ahtanum Creek Wapato Canal

Sunnyside Canal

Zillah STP 

Toppenish STP 

East Toppenish Drain 

Sub-Drain No. 35 

Granger STP 

Toppenish Creek Coulee Drain

Satus Creek 

South Drain

DID No. 7

RM 60.2 

RM 59.5 

12506000

RM 

23.1 

RM 5.3 

12500500

Sunnyside STP

Sulphur Creek

RM 0.8 

12508850

YAKIMA 

RIVER 

Kachess Kachess River 

Lake 

Kittitas Main Canal

Cle Elum WTP

Cle Elum STP

Teanaway River 

Kittitas Main Canal Return Flow 

Swauk Creek 

Taneum Creek 

West Side Ditch

Town Canal

Cascade Canal

Ellensburg Power Canal Outfall 

Manastash Creek 

Ellensburg STP 

Wilson Creek 

Naneum Creek 

Cherry 

Creek 

RM 

1.1 

RM 

20.0 

RM 0.6 

12476000 

RM 

0.9 

(Dam) 

RM 

8.2 

(Dam) 

RM 214.5 

(Dam) 

Cle Elum 

Lake 

RM 7.9 Cle Elum River 12479000

RM 3.7 

12480500

RM 5.5 

12483800

Keechelus 

Lake 

Union and Fruitvale Canals

NACHES RIVER Cowiche Creek 

Granger Drain 

Wapato STP Harrah STP 

Marion Drain

Simcoe Creek 

Umtanum Creek 

Roza Canal

Selah Creek 

Selah-Moxee Canal

Wenas Creek 

Selah STP 

Little Naches River 

American River 

Bumping River 

Rattlesnake Creek 

Naches-Selah Canal

Tieton Canal

Tieton River 

Wapatox Canal

Naches STP 

Wapatox Power Plant Return Flow 

Yakima WTP

Congdon Ditch

Naches-Cowiche Canal

Continued from bottom of previous column 

Rimrock 

Reservoir 

RM 21.3 

(Dam) 

RM 0.6 

12499000

RM 0.5 12488500

RM 16.6 

12488000

RM 19.4 

12489500

RM 20.9 

12491500

RM 14.2 

12492500

RM 44.6 

RM 27.8 

RM 18.4 

RM 13.9 

12506500

RM 4.0 

12501000

RM 2.7 

RM 2.7 

RM 

3.5 

DID No. 3

NACHES RIVER 

RM 44.2 

YAKIMA RIVER 

EXPLANATION

OUTFLOW FROM MAIN STEM

INFLOW TO MAIN STEM

GAGING STATION AND NO.

RIVER MILE

SEWAGE-TREATMENT PLANT

WATER-TREATMENT PLANT

DRAINAGE IRRIGATION DISTRICT

WTP

DID

STP

RM 140.4

12484500

wa19-0148_fig03-FlowChart

Figure 3. Selected tributaries, diversion canals, return flows, and streamflow-gaging stations, Yakima River basin, 

Washington.
Description of Study Area 7

(Vaccaro, 1995, 2002). Population growth in the basin was, 

and still is, the driving force behind the increased drilling 

of shallow domestic wells and deeper public water supply 

wells. Currently, there are more than 20,000 wells (fig. 4) in 

the basin. More than 70 percent of these wells are shallow, 

10–250 ft deep, domestic wells. On the basis of the digital 

water-rights database provided by WaDOE (R. Dixon, 

Washington State Department of Ecology, written commun., 

2001) and other information, at least 2,874 active groundwater 

rights are associated with the wells in the basin that can 

collectively withdraw an annual quantity of about 529,231 

acre-ft during dry years. The irrigation rights are for the 

irrigation of about 129,570 acres. There are about 16,600 

groundwater claims in the basin; these claims are for some 

270,000 acre-ft of groundwater (J. Kirk, Washington State 

Department of Ecology, written commun., 1998). ‘A water 

right claim is a statement of claim to water use that began 

before the state Water Codes were adopted, and is not covered 

by a water right permit or certificate. A water right claim does 

not establish a water right, but only provides documentation 

of one if it legally exists. Ultimately, the validity of claimed 

water rights would be determined through general water right 

adjudications’ (Washington State Department of Ecology, 

1998). A groundwater claim means a user claims that they 

were using groundwater continuously for a particular use, 

prior to 1945, when the State legislature enacted the Ground 

Water Code.

Overview of the Geology

The Columbia Plateau has been informally divided into 

three physiographic subprovinces (Meyers and Price, 1979). 

The western margin of the Columbia Plateau contains the 

Yakima Fold Belt subprovince and includes the Yakima River 

basin. The Yakima Fold Belt is a highly folded and faulted 

region, and within the study area it is underlain by various 

consolidated rocks ranging in age from Precambrian to 

Tertiary, and unconsolidated materials and volcanic rocks of 

Quaternary age. The simplified surficial geology (Fuhrer and 

others, 1994; more detail shown later) clearly shows the wide 

variety of rock materials present in the basin (fig. 5). In the 

Yakima River basin, the headwater areas in the Cascade Range 

include metamorphic, sedimentary, and intrusive and extrusive 

igneous rocks. The central, eastern, and southwestern parts of 

the basin are composed of basalt lava flows of the Columbia 

River Basalt Group (CRBG) with some intercalated sediments 

that are discontinuous and weakly consolidated. The lowlands 

are underlain by unconsolidated and weakly consolidated 

valley-fill comprising glacial, glacio-fluvial, lacustrine, and 

alluvium deposits that in places exceed 1,000 ft in thickness 

(Drost and others, 1990). Wind-blown deposits, called loess, 

are present locally along the lower valley.

irrigate about 500,000 acres. As part of the 1905 authorization 

and extensions, all forms of further appropriation of 

unappropriated water in the basin were withdrawn (Parker 

and Storey, 1916). Six dams were constructed as part of the 

Yakima Project: Bumping Dam in 1910, Kachess Dam in 

1912, Clear Creek Dam in 1914, Keechelus Dam in 1917, 

Tieton Dam (Rimrock Lake) in 1925, and Cle Elum Dam 

in 1933. The six reservoirs have a total capacity of about 

1.07 million acre-ft, of which about 78 percent is stored in 

the upper arm of the Yakima River and 22 percent is stored 

in the Naches River arm. The construction of the dams and 

other irrigation facilities resulted in an extremely complicated 

surface-water system (fig. 3). These Federal reservoirs 

provide water storage to meet irrigation requirements of the 

major irrigation districts at the time of year when the natural 

streamflow from unregulated streams can no longer meet 

demands; this time is referred to as the ‘storage control’ date. 

Several of the reservoirs also provide instream flows during 

the winter for the incubation of salmon eggs in redds (gravel 

spawning nests).

Legal challenges to water rights resulted in the 1945 

Consent Decree (U.S. District Court, 1945) that established the 

framework of how Reclamation operates the Yakima Project 

to meet water demands. The Decree determined two classes 

of rights—nonproratable and proratable. When the total water 

supply available (TWSA, defined as current available storage 

in the reservoirs, forecasted estimates of unregulated flow, and 

other sources that are principally return flows) is not sufficient 

to meet both classes of rights, the proratable (junior) rights are 

decreased according to the quantity of water available defined 

by the TWSA. As of 2008, the years when proration levels 

were defined were 1973, 1977, 1979, 1987–88, 1992–94, 

2001, and 2005. This legally mandated method, which was 

upheld in a 1990 court ruling, generally performs well in most 

years, but is dependent on the accuracy of the TWSA estimate. 

In some years, for example 1977, problems have arisen 

because of errors in the TWSA estimate (Kratz, 1978; Glantz, 

1982). In addition, numerous proratable users have obtained 

groundwater-water rights to pump supplemental water in the 

years that they receive prorated quantities of surface water. 

System management also accounts for defined instream flows 

at selected target points on the river, and for suggested changes 

in storage releases recommended by the Systems Operations 

Advisory Committee (SOAC)—the advisory board of fishery 

biologists representing the different stakeholders (Systems 

Operations Advisory Committee, 1999). The operations for 

meeting instream flows are most affected by a 1980 Federal 

district court decision and by Title XII of a Public Law that 

instituted (beginning in 1995) new instream flows at two 

diversions dams (Sunnyside and Prosser).

The drilling of numerous wells for irrigation was 

spurred by new (post 1945) well-drilling technologies, legal 

rulings, and the onset of a multi-year dry period in 1977 
8 Hydrogeologic Framework of the Yakima River Basin Aquifer System, Washington

wa19_0148_Fig04-Depth to GW

KITTITAS COUNTY

YAKIMA COUNTY

BENTON COUNTY

KLICKITAT COUNTY

YAKIMA COUNTY

C

A

S C A

D E R

A

N

G

E

T.

24

N.

T.

22

N.

T.

20

N.

T.

18

N.

T.

16

N.

T.

14

N.

T.

12

N.

T.

10

N.

T.

8

N.

T.

6

N.

R.10E. R.12E. R.14E. R.16E. R.18E. R.20E. R.22E. R.24E. R.26E. R.28E.

121°

47°

47°

30'

46°

121°30' 120°30' 120° 119°30'

46°

30'

0 5 10 20 30 MILES

0 5 10 20 30 KILOMETERS

EXPLANATION

0 to 50

51 to 100

101 to 250

251 to 500

501 to 1,000

1,001 to 3,500

Well depth, in feet

Bumping

Lake

S Fk

N Fk

Cle Elum River

Bumping River

Ahtanum Creek

Tieton River Wenas Creek

North Fork

Dry Creek

Creek

Toppenish

RIVER

YAKIMA

Satus

Creek

Cle

Elum

Lake

Rimrock

Lake

Kachess Lake

Keechelus Lake

Lake

Wallula

Teanaway River

Umtanum Creek

Little Naches River

Cowiche Creek

Cowiche Creek

River

Naches

RIVER

YAKIMA

RIVER

YAKIMA

Ellensburg

Toppenish

YAKIMA

Sunnyside

Richland

Kennewick

Valley-fill deposits and basalt lava flows are important for 

groundwater occurrence in the study area. The basalt consists 

of a series of flows erupted during various stages of the 

Miocene Age, from 17 to 6 million years ago. Basalt erupted 

from fissures located in the eastern part of the Columbia 

Plateau and individual flows range in thickness from a few 

feet to more than 100 ft. The total thickness in the central 

part of the plateau is estimated to be greater than 10,000 ft 

(Drost and others, 1990) and the maximum thickness in the 

study area is more than 8,000 ft. Unlike most of the Columbia 

Plateau, the CRBG in the Yakima Fold Belt is underlain by 

sedimentary rocks. The valley-fill deposits were eroded from 

the Cascade Range and from the east-west-trending anticlinal 

ridges that were formed by the buckling of the basalt sequence 

during mid- to late-Miocene time. Most of these deposits are 

part of the Ellensburg Formation. This formation underlies, 

Figure 4. Distribution of depths of water wells, Yakima River basin, Washington.
Description of Study Area 9

Figure 5. Simplified surficial geology, Yakima River basin, Washington.

wa19-0148_fig05_surficial geology

Kiona

Naches

Yakima

Wapato

Prosser

Cle Elum

Sunnyside Richland

Union Gap

Ellensburg

Toppenish

121°

47°

47°

30'

46°

121°30' 120°30' 120° 119°30'

46°

30'

0 5 10 20 30 40 MILES

0 5 10 20 30 40 KILOMETERS

EXPLANATION

Simplified surficial geology

Quaternary flood deposits

Quaternary deposits, loess

Quaternary and Pliocene volcanic rock

Columbia River Basalt Group rock

Miocene and older volcanic rock

Tertiary granitic and intermediate intrusive rock

Non-marine sedimentary rock

Marine sedimentary rock

Pre-Tertiary metamorphic and intrusive rock

T.

24

N.

T.

22

N.

T.

20

N.

T.

18

N.

T.

16

N.

T.

14

N.

T.

12

N.

T.

10

N.

T.

8

N.

T.

6

N.

R.10E. R.12E. R.14E. R.16E. R.18E. R.20E. R.22E. R.24E. R.26E. R.28E.

intercalates, and overlies the basalts along the western edge, 

and constitutes most of the thickness of the unconsolidated 

deposits (informally called the overburden; Drost and others, 

1990) in the basins. The basins are narrow to large open 

synclinal valleys between the numerous anticlinal ridges.

The deposition of a thick, upper sequence of sand, gravel, 

and some fine-grained material is the result of erosion by 

glacial ice and transport by meltwater streams. Damming of 

large lakes by glacial ice during the Pleistocene epoch resulted 

in the deposition of silt and clay beds in parts of the uplands. 

When the lakes drained, the fine sediments were exposed, 

subsequently eroded by wind, and deposited over the lower, 

eastern parts of the study area. Thus, the unconsolidated 

materials in the basins that abut and are interbedded with the 

basalts range in age from Miocene to Holocene.
10 Hydrogeologic Framework of the Yakima River Basin Aquifer System, Washington

Well Information

References to Wells

Wells discussed in this report are identified by USGS 

well number, as described in section “Well-Numbering 

System.” A well number without sequence number indicates 

that the well is not in the USGS National Water Information 

System (NWIS) and that the well information is based 

on a log obtained from WaDOE. Except when discussing 

hydrochemistry in section “Methane,” well numbers are not 

shown in maps. Instead, townships and ranges of the Public 

Land Survey System are identified in most maps, which allows 

the general determination of well locations based on USGS 

well numbers. This approach provides the option of generally 

locating a specific well in a variety of maps, such as those 

showing groundwater recharge or pumpage. 

Well Data and Their Use

Four sets of water-level measurements in wells 

throughout the study area were conducted during the study. 

The measurements were made in autumn 2000, spring 2001, 

autumn 2001, and spring 2002. In addition, YN staff made 

monthly measurements at numerous wells, as well as weekly 

measurements at nine wells during the period of interest (June 

2000–June 2002). A total of about 8,300 water levels were 

measured during this latter period. The measured wells were 

selected to obtain a good spatial distribution, both laterally and 

vertically; the location of wells with water-level measurements 

during the period June 2000 through June 2002 is shown in 

figure 6. In addition, historical water-level measurements 

made by WaDOE and YN that had not been entered into 

NWIS were compiled. Information and water levels for all 

these wells were put into NWIS.

Additional historical water levels were available from 

more than 8,000 wells. A subset of these water levels, which 

is in NWIS, was measured by the USGS. A second subset 

of these water levels also is in NWIS, and represents water 

levels reported on drillers’ well logs. A third subset of water 

levels consists of water levels reported on ‘uncoded’ well 

logs. Uncoded well logs were any well logs in USGS paper 

files that were not in NWIS. Selected information from more 

than 9,000 of these uncoded wells was put into digital form in 

order to provide additional information for: (1) mapping the 

spatial distribution of wells in the basin (fig. 4), (2) evaluating 

the spatial distribution of well depths, (3) analyzing specificcapacity tests, (4) identifying flowing wells, and (5) mapping 

water levels. Information on specific-capacity tests and water 

levels was not available for all of the uncoded wells.

During this study, well information from the described 

data sets was used for constructing various maps and 

for analysis of the flow system. For example, lithologic 

information from more than 6,500 wells was used by Jones 

and others (2006) and Jones and Vaccaro (2008) to map 

hydrogeologic units. All of the water-level data also was used 

in some capacity in the study, for example, examining the 

relation of water levels to well depth and for data in-filling in 

areas with sparse water-level measurements in 2000–02. All 

available information for flowing wells and specific-capacity 

tests also was utilized.

Hydrogeologic Units

Thirty-four hydrogeologic units were mapped and 

named in this study by Jones and others (2006) and Jones and 

Vaccaro (2008). Hydrogeologic unit information for the 28 

major units is summarized in table 1 and a correlation chart 

showing the relation between generalized geologic units and 

hydrogeologic units is shown in table 2. Information used to 

help define and map the hydrogeologic units in table 2 is from 

well logs and published maps of Swanson and Wright (1978), 

Swanson and others (1979a, b), Tanaka and others (1979), 

Tabor and others (1982, 1987, 1993), Walsh (1986a, b), 

Korosec (1987), Phillips and Walsh (1987), Schasse (1987), 

Gulick and Korosec (1990), Reidel and Fecht (1994a, 1994b), 

and Schuster (1994a, 1994b, 1994c). Most of the maps in the 

post-1980 publications were available in digital form from the 

Washington State Department of Natural Resources (2002). 

Additional information for the Hanford Site was provided 

by S.P. Reidel and P.D. Thorne (Battelle Institute, written 

commun., 2003 and 2005) and for the Toppenish basin by 

Newell Campbell (unpub. maps, produced for the Yakama 

Nation, 2001).

Information about the hydrogeologic units defined and 

mapped in this study is summarized below. A more detailed 

description of the study methods and hydrogeologic units can 

be found in Jones and others (2006) and Jones and Vaccaro 

(2008). The detailed descriptions include such aspects as maps 

of thickness of selected units, depths to the top of selected 

units, and hydrogeologic sections.

There are four categories of hydrogeologic units: 

(1) unconsolidated units composed of Pliocene to Recent 

sediments that may or may not be subdivided, (2) semiconsolidated to consolidated units (referred to here as 

consolidated units) composed of Miocene-Pliocene sediments, 

(3) Miocene CRBG and interbed units, and (4) Paleozoic 

to Quaternary bedrock units. The first 2 categories include 

19 mapped units (pl. 1) and 6 subunits of one mapped 
Hydrogeologic Units 11

Figure 6. Location of wells with water-level measurements, June 2000 through June 2002, Yakima River basin, Washington.

wa19_0148_Fig06-6/00 through 6/02

KITTITAS COUNTY

YAKIMA COUNTY

BENTON COUNTY

KLICKITAT COUNTY

YAKIMA COUNTY

C

A

S C A

D E R

A

N

G

E

T.

24

N.

T.

22

N.

T.

20

N.

T.

18

N.

T.

16

N.

T.

14

N.

T.

12

N.

T.

10

N.

T.

8

N.

T.

6

N.

R.10E. R.12E. R.14E. R.16E. R.18E. R.20E. R.22E. R.24E. R.26E. R.28E.

121°

47°

47°

30'

46°

121°30' 120°30' 120° 119°30'

46°

30'

0 5 10 20 30 MILES

0 5 10 20 30 KILOMETERS

EXPLANATION

Well with water-level measurement

 June 2000 through June 2002

Bumping

Lake

S Fk

N Fk

Cle Elum River

Bumping River

Ahtanum Creek

Tieton River Wenas Creek

North Fork

Dry Creek

Creek

Toppenish

RIVER

YAKIMA

Satus

Creek

Cle

Elum

Lake

Rimrock

Lake

Kachess Lake

Keechelus Lake

Lake

Wallula

Teanaway River

Umtanum Creek

Little Naches River

Cowiche Creek

Cowiche Creek

River

Naches

RIVER

YAKIMA

RIVER

YAKIMA

Ellensburg

Toppenish

YAKIMA

Sunnyside

Richland

Kennewick

unconsolidated unit. These two categories consist of basinfill deposits occurring in six structural-sedimentary basins 

(fig. 7), herein called structural basins; the geologic structure 

delineating the basins is clearly defined by the folds and 

faults shown on figure 7. The structural basins generally 

are consistent with the groundwater basins of Kinnison and 

Sceva (1963). Each unit in a structural basin has been named; 

for example, a unit in the Kittitas basin that is composed of 

alluvial deposits is named Unit 1 (Jones and others, 2006, 

table 2). These names, however, may not represent the same 

type of hydrogeologic unit in different structural basins or 

represent the same geologic units. For each structural basin, 

the naming of these units starts at 1 for the uppermost unit 

and increases with the depth (age) of a unit; thus, if there were 

three units in a structural basin, they would be numbered 1 

through 3.
12 Hydrogeologic Framework of the Yakima River Basin Aquifer System, Washington

Table 1. Information for the hydrogeologic units of the Yakima River basin aquifer system, Washington.

[Abbreviations: mi2, square mile; ft, foot; –, not calculated]

Structural basin 

name

Mapped 

area (mi2

) Unit Lithology

Thickness (ft)

Range Average Median

Roslyn basin 70 1 Alluvial, lacustrine, and glacial

deposits

0 to 360 80 80

2 Fine-grained lacustrine clay and silt

deposits

0 to 530 180 170

3 Coarse-grained sand and gravel

deposits

0 to 240 60 50

Total basin thickness All deposits 0 to 700 150 110

Kittitas basin 270 1 (alluvial) Floodplain alluvial deposits 0 to 100 30 10

2 (unconsolidated) Loess, alluvial fan, glacial terrace,

and Thorp gravel deposits

0 to 790 180 150

3 (consolidated) Ellensburg Formation and undefined

continental sedimentary deposits

0 to 2,040 600 350

Total basin thickness All deposits 0 to 2,120 500 270

Selah basin 170 1 (alluvial) Floodplain alluvial deposits 0 to 90 30 30

2 (unconsolidated) Loess, alluvial fan, glacial terrace,

and Thorp gravel deposits

0 to 290 50 40

3 (consolidated) Ellensburg Formation and undefined

continental sedimentary deposits

0 to 1,920 320 200

Total basin thickness All deposits 0 to 1,920 300 200

Yakima basin 230 1 (alluvial) Floodplain alluvial deposits 0 to 120 20 20

2 (unconsolidated) Loess, alluvial fan, glacial terrace,

and Thorp gravel deposits

0 to 350 90 80

3 (consolidated) Ellensburg Formation and undefined

continental sedimentary deposits

0 to 1,840 510 450

Total basin thickness All deposits 0 to 1,840 530 410

Toppenish basin 440 1 (fine-grained 

unconsolidated)

Touchet Beds, terrace, loess, and

some alluvial deposits

0 to 80 10 10

2 (coarse-grained 

unconsolidated)

Coarse-grained sand and gravel

deposits

0 to 270 90 80

3 (consolidated) Consolidated deposits of the upper

Ellensburg Formation and undefined

continental sedimentary deposits

0 to 970 350 320

4 (fine-grained deposits) Top of Rattlesnake Ridge unit of the

Ellensburg Formation or ‘Blue Clay

unit’

0 to 520 170 140

5 (coarse-grained 

deposits)

Base of Rattlesnake Ridge unit of

the Ellensburg Formation

0 to 140 20 20

Total basin thickness All deposits 0 to 1,210 550 550
Hydrogeologic Units 13

Benton basin 1,020 1 (unconsolidated) Alluvial, alluvial fan, loess, terrace,

dune sand, Touchet Beds, Missoula

flood, and Ringold Formation deposits.

0 to 870 120 70

2 (consolidated) Ellensburg Formation and undefined

continental sedimentary deposits

0 to 680 100 60

Total basin thickness All deposits 0 to 870 120 60

Unit name Mapped 

area (mi2

) Extent (mi2

) Lithology

Thickness (ft)

Range Average Median

Columbia River Basalt Group and interbeds 

Saddle 

Mountains 

unit

2,289 457 mi2 surface outcrop, 

1,804 mi2 below surface,

28 mi2 not present in

mapped area

 Saddle Mountains

Basalt flow members and interbeds

 0 to 1,110 550 560

Mabton Interbed 2,206 2,179 mi2 below surface,

27 mi2 not present in

mapped area 

0 to 250 70 70

Wanapum unit 3,444 659 mi2 surface outcrop,

2,757 mi2 below surface,

28 mi2 not present in

mapped area

Wanapum Basalt flow members and

interbeds

0 to 1,180 600 490

Vantage 

Interbed

3,087 3,047 mi2 below surface,

40 mi2 not present in

mapped area

0 to 135 30 20

Grande Ronde 

unit

5,383 1,547 mi2 surface

outcrop, 3,786 mi2

below surface, 50 mi2

not present in mapped

area

Grande Ronde Basalt flow members

and interbeds

– – –

Bedrock units 

Quaternary 

bedrock

82 Principally volcanics, but with minor 

amounts of sediments

– – –

Tertiary 1,300 Sediments, and volcanic and plutonic 

rocks

– – –

Mesozoic 136 Metamorphic, volcanic, and plutonic 

rocks

– – –

Paleozoic 2 Metamorphic rocks – – –

All bedrock 

units

1,520 – – –

Table 1. Information for the hydrogeologic units of the Yakima River basin aquifer system, Washington.—Continued

[Abbreviations: mi2, square mile; ft, foot; –, not calculated]
14 Hydrogeologic Framework of the Yakima River Basin Aquifer System, Washington

Table 2. Correlation chart showing the regional relation between generalized geologic and hydrogeologic units in the basin-fill and 

Columbia River Basalt Group units, and bedrock units for the Yakima River basin aquifer system, Washington.

[Hydrogeologic unit: B, Benton basin; R, Roslyn basin; K, Kittitas basin; S Selah basin; T, Toppenish basin; Y, Yakima basin. Abbreviations: Fm., formation; 

Mtn, mountain; Cr., creek]

BASIN-FILL AND COLUMBIA RIVER BASALT GROUP UNITS

ERA PERIOD EPOCH SIMPLIFIED GEOLOGIC UNITS HYDROGEOLOGIC UNIT CENOZOIC Quaternary

Holocene Alluvium, alpine glaciation, alluvial fan, dune sand, artificial fill, and peat deposits Unit 1 (R, K, S. Y, T, B)

Pleistocene

Alluvium, alpine glacial drift, alluvial fan, Palouse Fm., Lakedale Drift, Lookout Mountain

Ranch Drift, Hayden Creek Drift, Kittitas Drift, Evans Creek Drift, unknown continental

sedimentary deposits, dune sand, Missoula glacial lake deposits

Unit 1 (R, K, S, Y, T, B),

Unit 2 (R, K, S, Y, T)

Tertiary

Pliocene Alluvial fan, Ringold Fm., Ellensburg Fm., Dalles Fm., Thorpe Gravel, and unknown

continental sedimentary deposits

Unit 1 (B),

Unit 2 (R, K, S, Y, T),

Unit 3 (R, K, S, Y)

Miocene

Ellensburg Fm., Ringold Fm., Dalles Fm., Snipes Mountain deposits, and unknown

continental sedimentary deposits

Unit 2 (B),

Unit 3 (R, K, S, Y, T),

Unit 4 (T),

Unit 5 (T)

Columbia River Basalt Group

Saddle Mountains Basalt flow members and interbeds Saddle Mountains unit (SM)

Mabton interbed Mabton unit

Wanapum Basalt flow members and interbeds Wanapum unit (WN)

Vantage interbed Vantage unit

Grande Ronde Basalt flow members and interbeds Grande Ronde unit (GR)
Hydrogeologic Units 15

BEDROCK UNITS

ERA PERIOD EPOCH SIMPLIFIED GEOLOGIC UNITS HYDROGEOLOGIC UNIT CENOZOIC Quaternary

Holocene to

Pleistocene

Old Snowy Mtn. andesite, Mount Rainier andesite, Tieton andesite, Russel Ridge andesite, 

Round Mtn. andesite, Pear Lake andesite, Jess Lake comjplex andesite, Deep Creek andesite,

Deer Lake Mtn. andesite, Swampy Meadow andesite, Signal Peak andesite, South Butte

andesite, Hellroaring and Big Muddy Creek complex andesite, Mt. Adams volcanics, Tumac 

Mtn. basalt, Rimrock Lake basalt, Lava Creek basalt, Kincaid Lake basalt, Hogback Mtn. 

basalt, Canyon Creek basalt, Paradise Falls basalt, Outlaw Creek basalt, McClellan Meadows 

basalt, White Chuck cinder cone basalt, Walupt Lake basalt, Two Lakes Basalt, Trout Lake 

Creek basalt, Thomas Lake basalt, TIllicum Creek basalt, Twin Buttes basalt,Sleeping Beauty 

basalt, Sawtooth Mtn. basalt, Red Lake basalt, Riley Creek basalt, Rush Creek basalt, Red 

Butte basalt, Mosquito Creek basalt, Lakeview Mtn. basalt, Little Goose Creek basalt, Loaf 

basalt, Lake Comcomly basalt, Lone Butte basalt, Indian Viewpoint basalt, Indian Heaven 

basalt, Ice Cave basalt, Hidden Lake basalt, Goat Butte basalt, Green Canyon basalt, Gotchen 

Creek basalt, Glaciate Butte basalt, Flattop Mtn. basalt, East Canyon Creek basalt, Dead 

Horse Creek basalt, Deep Lake basalt, Camas Prairie basalt, County Park basalt, Chenamus 

Lake basalt, Burnt Peak basalt, Bunnell Butte basalt, Bird Mountain basalt, Blue Lake basalt, 

Badger Peak basalt, Placid Lake basalt, Spiral Butte dacite, Clear Fork dacite, Snyder Mtn. 

dacite, Olallie Lake dacite

QB

Quaternary Bedrock unit

(for area that overlays

the older bedrock

deposits and lies outside

the Grande Ronde

Basalt extent)

Pliocene

Simcoe Mtn. volcanics, Devils Horns volcanics, Goat Rocks andesite, Bee Flat andesite, 

Lincoln Plateau basalt, Hogback Mtn. basalt, Devils Washbasin basalt, Dalles Ridge basalt,

Bald Mtn., pluton, and Bethel Ridge basalt

TB

Tertiary Bedrock unit

Tertiary

Miocene

Conglomerate Point breccia, Howson andesite, Council Bluff volcanics, Clear West rhyolite,

Silver Creek tonalite, Skyscraper Mtn. volcanics, Eagle tuff, Palisades tuff, Ellensburg Fm. 

volcanics, Cooper Pass volcaniclastics, Stevens Ridge Fm. volcanics, Fife’s Peak Fm.

volcanics, Tatoosh pluton, Bumping Lake pluton, Box Canyon gabbro, Carbon River stock,

Nisqually diorite, Jug Lake sills, Snoqualmie Batholith, Snipes Peak Fm. sediments, White River

pluton, Box Canyon volcanics

Oligocene

Wenatchee Fm. sediments, Chumstick Fm. andesite, Grotto Batholith, Mount Daniel volcanics,

Index Batholith, Mount Aix volcanics, Eagle Gorge volcanics, Ohanapecosh Fm. volcanics, Mill 

Creek basalt, Wildcat Creek volcaniclastics, Spencer Creek volcaniclastics, Rattlesnake Creek

tuff, Bumping River tuff, and Burnt River tuff

Eocene

Tukwila Fm. volcanics, Tiger Mtn. Fm., sediments, Roslyn Fm. sediments, Renton Fm. sediments, 

Naches Fm. sediments and volcanics, Barlow Pass volcanics, Swauk Fm. sediments and

volcanics, Manatash Fm. sediments, Lookout Creek sandstone, Tenaway Basalt, Camas Land

diabase, Goat Mtn. dacite, Banks Lake dacite, Fuller Mount polug, Cooper Mtn. Bartholith

Raging River Fm. sediment, Mt. Persis volcanics, Taneum andesite, Summer Creek basalt,

Peoh Point andesite, Frost Mtn. basalt, Chumstick Fm. volcanics, and Spencer Creek tuff,

Tieton Pass basalt, Discovery Creek basalt

Paleocene Swawilla Basin granite, Coffee Lake granite

MESOZOIC

Cretaceous

Early to Late Nason Ridge Gneiss, Mount Stuart Batholith, Bald Mtn. pluton, Arbuckle Mtn. tonalite, Russell

Branch Fm. sediments, Ten Peak pluton, Sloan Creek pluton

MB

Mesozoic Bedrock unit

Jurassic

Early to Late

Lookout Mountain Fm. metamorphics and metavolcanics, Alta Lake metamorphics, Ingalls

tectonic complex metamorphics and metavolcanics, eastern and western melange elt

metavolcanics, Indian Creek complex diorite, Sarrington phyllite, Shuksan greenschist, Quartz

Mtn. stock tonalite

Triassic

Early to Lake Tonga Fm. metamorphics and metavolcanics, Gibraltar Rock migmatite, Chiwaukim schist

PALEOZOIC

Permian

Early to Late North Peak metavolcanics

PB

Paleozoic Bedrock unit

Table 2. Correlation chart showing the regional relation between generalized geologic units and hydrogeologic units basin-fill and 

Columbia River Basalt Group units, and bedrock units for the Yakima River basin aquifer system, Washington.—Continued
16 Hydrogeologic Framework of the Yakima River Basin Aquifer System, Washington

wa19_0148_Fig07-Structure

121°

47°

47°

30'

46°

121°30' 120°30' 120° 119°30'

46°

30'

KITTITAS COUNTY

YAKIMA COUNTY

COUNTY

BENTON COUNTY

KLICKITAT

COUNTY

YAKIMA

Bumping

Lake

S Fk

N Fk

Cle Elum River

Bumping River

Ahtanum Creek

Tieton River Wenas Creek

North Fork

Dry Creek

To

Creek ppenish

RIVER

YAKIMA

Satus

Creek

Cle

Elum

Lake

Rimrock

Lake

Kachess Lake

Keechelus Lake Teanaway River

Umtanum Creek

Little Naches River

Cowichee Creek

Cowichee Creek

River

Naches

RIVER

YAKIMA

RIVER

YAKIMA

COLUMBIA 

RIVER

COLUMBIA RIVER

So. Fork

No. Fork

Cle Elum

Parker

Wapato

Ellensburg

Umtanum

Kittitas Thrall

Toppenish

Moxee

City Union Gap

Yakima

Selah

Naches

Sunnyside

Richland

Kiona

Kennewick

Prosser

Grandview

Mabton

Satus

Zillah

Granger

Roza

Easton

Teanaway

Tieton Rimrock

0 5 10 20 30 MILES

0 5 10 20 30 KILOMETERS

EXPLANATION

Roslyn

Kittitas

Selah

Yakima

Extended Toppenish

Eastern Benton

Basins

Fault

Fold

WASHINGTON

Extended

study area

Base from U.S. Geological Survey and (or) Washington Division

of Geology and Earth Resources digital data, 1983, 1:100,000

Universal Transverse Mercator projection, Zone 10

Horizontal Datum: North American Datum of 1927 (NAD 27)

Vertical Datum: North American Vertical Datum of 1988 (NAVD 88)

Moxee

Ahtanum

Syncline

Toppenish Ridge

Wahluke Syncline

Cold Creek Syncline

Kittitas Valley Syncline

Naneum Ridge Anticline

Manastash Anticline

Umtanum Anticline

Horse Heaven Hills Structure

Ainsley Canyon Anticline

Laurel Hill Monocline

Taneum Monocline

Cleman Mtn. Anticline

Ahtanum Ridge

Wapato Syncline

Wenas Syncline

 Rattlesnake Hills 

Structure

Yakima Ridge

Hog

Ranch Structure

Medicine Valley Syncline

Wilson Creek Monocline

Reeser Canyon

Monocline

Naneum Creek

Monocline

T.

24

N.

T.

22

N.

T.

20

N.

T.

18

N.

T.

16

N.

T.

14

N.

T.

12

N.

T.

10

N.

T.

8

N.

T.

6

N.

R.10E. R.12E. R.14E. R.16E. R.18E. R.20E. R.22E. R.24E. R.26E. R.28E.

Figure 7. Location of six structural basins and geologic structure, Yakima River basin aquifer system, Washington.
Hydrogeologic Units 17

In the Kittitas, Selah, and Yakima basins (fig. 7), an 

alluvial unit (Unit 1), an unconsolidated unit (Unit 2), 

and a consolidated unit (Unit 3) were mapped (pl. 1); the 

Yakima basin also is locally called the Ahtanum-Moxee 

basin (Ahtanum and Moxee subbasins). In the Roslyn basin, 

a surficial coarse-grained aquifer unit (Unit 1), a lacustrine 

confining unit (Unit 2), and a confined coarse-grained aquifer 

unit (Unit 3) underlying the confining unit were mapped 

(table 2, pl. 1). In the Toppenish basin, five units were mapped 

that consist of coarse-grained and fine-grained unconsolidated 

deposits and three units comprised of part of the Ellensburg 

Formation. An unconsolidated unit (Unit 1) and a consolidated 

unit (Unit 2) were mapped in the Benton basin. In addition, 

in the eastern part of the Benton basin (area shown on plate 1 

as a subbasin), the unconsolidated unit (the only unit present 

in this area) was further divided into six subunits (Jones and 

others, 2006). These six subunits, which occur together only 

in this part of the study area, consist of fluvial and lacustrine 

deposits of the Ringold Formation, glaciofluvial sediments 

of the Hanford Formation, and pre-Missoula Flood gravels. 

Typically, the consolidated units contain deposits that are more 

consolidated (for example, sandstone) than the deposits of the 

unconsolidated units (for example, recent sand and gravel).

The structural-basin boundaries (fig. 7) are slightly 

different than those shown in Jones and others (2006) in 

order to provide an improved framework for constructing 

a groundwater flow model. These differences include an 

extension of the Toppenish basin to include the western part of 

the Benton basin where both unconsolidated and consolidated 

units are present. Also, the eastern part of the Benton basin 

containing the six unique subunits was extended eastward 

to the Columbia River, to include about 217 mi2 outside the 

Yakima River basin. This area generally coincides with the 

Hanford Site and is part of what is herein called the extended 

study area. The extents of the six eastern Benton basin 

subunits were not mapped during this study but were obtained 

from S.P. Reidel and P.D. Thorne (Battelle Institute, written 

commun., 2003 and 2005). To distinguish these extended areas 

from the previously defined structural basins, they are referred 

to as the extended Toppenish basin and the Eastern Benton 

basin (fig. 7).

The unconsolidated units include alluvial, alluvial fan, 

terrace, glacial, loess, lacustrine, and flood (Touchet Beds) 

deposits that range from coarse-grained gravels to fine-grained 

clays, with some cemented gravel (Thorp gravel and similar 

unnamed gravels). Most of the unconsolidated units consist of 

coarse-grained deposits. 

The deposits that constitute the consolidated units 

are principally deposits of the Ellensburg Formation, but 

also include some undifferentiated continental sedimentary 

deposits. These units include continental sandstone, shale, 

siltstone, mudstone, claystone, clay, and lenses or layers of 

uncemented and weakly to strongly cemented gravel and sand 

(conglomerate). These clastic deposits are one of the most 

stratigraphically complex parts of the aquifer system. In the 

structural basins where these deposits overlie bedrock they 

were either mapped as one hydrogeologic unit (called the 

consolidated unit, for example, Unit 3 in the Kittitas, Selah, 

and Yakima basins and Unit 2 in the Benton basin) or they 

were subdivided into several hydrogeologic units as in the 

Toppenish basin (Jones and others, 2006, table 2). Except 

for the Mabton and Vantage Interbeds, where the Ellensburg 

Formation is interbedded with the CRBG, it was considered 

part of the CRBG hydrogeologic units (Jones and Vaccaro, 

2008). The Mabton and Vantage Interbeds are considered 

separate hydrogeologic units and the depth to the top of these 

units was mapped by Jones and Vaccaro (2008).

The lithology of the consolidated units varies from the 

Kittitas basin to the extended Toppenish basin; consolidated 

units are absent in the Roslyn and Eastern Benton basins. The 

variations are due to spatial-temporal variations in deposition, 

erosion, and structural deformation (faulting and folding). 

Examples of the spatial variations in lithology based on seven 

well logs are presented below. In the Kittitas basin, at well 

17N/18E-01C01, which yields more than 1,000 gal/min, the 

consolidated unit (Unit 3) is overlain by the unconsolidated 

unit (Unit 2) that is about 400 ft thick. This 1,209-ft deep 

well penetrates about 800 ft of clay, sand, and gravel of the 

consolidated unit, and only 6 ft of shale was penetrated near 

the bottom. In contrast, in the Selah basin, a 1,955 ft well 

(15N/17E-36A01) with a yield of 900 gal/min penetrates 

more than 1,800 ft of the consolidated unit (Unit 3). In the 

upper section of this well is a 411-ft thick sandstone section 

underlain by about 1,110 ft of mainly clay with lenses of 

sand and gravel and some conglomerate; about one-half 

of the remaining deposits are sandstone. A nearby 1,200-ft 

well (15N/17E-27A) penetrates predominantly sandstone 

(with some cemented gravel layers) from about 38 ft to 

the bottom of the well; the driller reported only a trace of 

water (5–6 gal/min) at 1,100 ft. In the Yakima basin, the 

consolidated unit in a 1,200-ft deep well (13N/18E-35K01) 

is overlain by about 650 ft of sand, gravel, and cobbles with 

minor amounts of clay. From about 650 to 1,032 ft, the 

consolidated unit consists principally of clay and layers of 

sand and gravel, and only a 5-ft interval in which a shale/

sandstone layer was penetrated. Clay and sandstone were 

penetrated from 1,032 to 1,075 ft before the CRBG was 

reached. In contrast, in the Moxee subbasin of the Yakima 

basin, a 637-ft well (12N/20E-8F01) penetrated clay, 

sandstone, and shale to its final depth and only minor amounts 

of interbedded sands and gravels were present. Lastly, near the 

central part of the Toppenish basin, a 1,471-ft well (11N/18E26M03), which reached basalt at 960 ft, penetrated about 

110 ft of gravel, boulders, and sand with some clay before 

penetrating 851 ft of clay with layers of sand and gravel 

intermixed with clay (shale and sandstone where absent). 

Well 11N/20E-12H01 (1,168-ft deep) in the Toppenish basin 

penetrated mainly shale, sandstone, and clay before reaching 

basalt at 758 ft. 
18 Hydrogeologic Framework of the Yakima River Basin Aquifer System, Washington

The other two categories of units are the Miocene age 

CRBG units and Paleozoic to Quaternary bedrock units 

(table 2). The CRBG units form the major, productive 

volcanic-rock part of the aquifer system. The generally older, 

non-CRBG bedrock units (herein called bedrock units) are 

present mainly along the northern, northwestern, and western 

margins of the basin (fig. 5) and include volcanic, intrusive, 

marine and nonmarine sedimentary, and metamorphic rock 

units. In a few areas at the western margins of the basin in the 

High Cascades, younger rock units composed principally of 

Quaternary volcanics units are present (table 2). These include 

the Tieton andesite and the Mount Adams volcanics that were 

derived from the volcanically active Cascade Range.

The CRBG contains three formations in the study area, 

from oldest to youngest, the Grande Ronde, Wanapum, and 

Saddle Mountains Basalts (table 2). The Grande Ronde Basalt 

is the most extensive, consisting of 85 to 88 percent of the 

total volume of the CRBG and the Saddle Mountains Basalt is 

the least extensive, consisting of less than 2 percent of the total 

volume of the CRBG (Reidel, 1982; Tolan and others, 1989). 

The younger Saddle Mountains Basalt contains the thickest 

and most sedimentary interbeds, especially in the Yakima Fold 

Belt, because of its episodic eruptions and proximity to source 

material. For example, a 773-ft deep well (11N/21E-34C01) 

penetrated the Saddle Mountains Basalt from 17 to 70 ft and 

then penetrated clay, sand, sandstone, and gravel to 587 ft, 

followed by 34 ft of basalt that was underlain by 152 ft of 

interbeds. A nearby well (11N/21E-36J01) penetrated 400 ft of 

sand and clay before penetrating 50 ft of the Saddle Mountains 

Basalt; 270 ft of sand and clay underlies the basalt to the final 

depth of 720 ft. There are locations where the interbeds in the 

Saddle Mountains Basalt comprise more than 50 percent of the 

total thickness of the formation.

Each CRBG formation was defined as a hydrogeologic 

unit (table 2). The formations are called units because they 

include interbeds. Each unit includes a thick sequence of 

basalt flows that overlap and intermingle. In turn, individual 

basalt flows comprise the members of the formations. The 

depth to the top of each unit was mapped by Jones and 

Vaccaro (2008), and the configuration of the top of each unit 

is very complex, as indicated by the altitude of unit tops 

(pl. 2). The Mabton and Vantage Interbeds also were defined 

as hydrogeologic units and depths to their tops were mapped 

by Jones and Vaccaro (2008). The Mabton unit lies between 

the Saddle Mountains and Wanapum units and the Vantage 

unit separates between the Wanapum and Grande Ronde 

units. Neither the Mabton nor the Vantage units are present 

throughout the extent of the overlying CRBG units. The 

maps showing the depth to the tops include the area east of 

the Yakima River basin boundary to the Columbia River, an 

area of about 700 mi2. This additional area, combined with 

the Yakima River basin, is called the extended study area and 

encompasses about 6,900 mi2. The extended study area thus 

is bounded on the east by the Columbia River, a hydrologic 

boundary in the regional groundwater flow model that is being 

constructed as part of this study. 

Discontinuous and generally small patches of CRBG 

formations were not combined with underlying formations 

because WaDOE generally manages withdrawals from the 

CRBG on the basis of formations. Within the extended study 

area, the lateral extent of the Grande Ronde unit is about 

5,383 mi2 (its thickness was not estimated due to insufficient 

data), the extent of the Wanapum unit is about 3,444 mi2 

and has an average thickness of about 600 ft, and the Saddle 

Mountains unit extent is about 2,289 mi2 and has an average 

thickness of about 550 ft (table 1). 

Four bedrock units were defined on the basis of their 

age. These units are called the Paleozoic unit, the Mesozoic 

unit, the Tertiary unit, and the Quaternary bedrock unit. 

The Paleozoic unit consists of metamorphic rocks and 

the Mesozoic unit has three subdivisions consisting of 

metamorphic, volcanic, and plutonic rocks. The Tertiary 

unit also has three subdivisions consisting of sedimentary, 

volcanic, and plutonic rocks. The Quaternary bedrock unit 

consists principally of volcanics, but in a few small areas it 

consists of sediments (pl. 2). Where not overlain by younger 

deposits, the surficial extents of these bedrock units were 

obtained from the digital GIS database for Washington 

(Washington State Department of Natural Resources, 2002). 

Neither thickness nor vertical subdivisions for these units 

were mapped due to a lack of information. The formations 

that comprise these units, such as the nonmarine sandstone 

of the Eocene age Roslyn and Swauk Formations, which 

are separated by the Teanaway Basalt, and the interbedded 

sandstone-basalt Naches Formation are as much as 5,000 ft 

thick (Kinnison and Sceva, 1963; Campbell, 1989). The 

combined lateral extents of these units where they abut the 

CRBG are about 1,520 mi2. Within this area, these units 

either crop out (pl. 2) or underlie unconsolidated and (or) 

consolidated deposits. The Mesozoic and Tertiary units also 

underlie the CRBG and the Quaternary bedrock unit overlies 

either the CRBG or the Mesozoic and Tertiary units.

The lateral extents of the hydrogeologic units are shown 

on plates 1 and 2, and their surficial extents are shown in 

figure 8. For the CRBG units, plate 2 also shows the altitude 

(a shaded relief map) of the top of the unit, and where a unit 

outcrops, its altitude will be land surface. Note that the basinfill units in the structural basins are aggregated for display 

purposes (detailed extents of these units are shown on plate 

1 and the mapped thickness of units are shown in Jones and 

others (2006)). The area shown on plate 2 and figure 8, which 

is the 6,900 mi2 extended study area, includes both the Eastern 

Benton basin and the area outside of the Yakima River basin 

where the basalt units were mapped. Deposits that are similar 

to the basin-fill deposits outside of the six structural basins 

are included on figure 8 to show their limited extent. These 

deposits are considered part of the underlying hydrogeologic 

unit and they are not important components of the regional 

groundwater flow system. Information on the area and 

thickness of the units and their components (table 1) and the 

correlation chart (table 2) indicate the complex make-up of the 

Yakima River basin aquifer system.
Hydrogeologic Units 19

wa19_0148_Fig08-SurfHydro Units

KITTITAS COUNTY

YAKIMA COUNTY

COUNTY

BENTON COUNTY

KLICKITAT

COUNTY

YAKIMA

Bumping

Lake

S Fk

N Fk

Cle Elum River

Bumping River

Ahtanum Creek

Tieton River Wenas Creek

North Fork

Dry Creek

Creek

Toppenish

RIVER

YAKIMA

Satus

Creek

Cle

Elum

Lake

Rimrock

Lake

Kachess Lake

Keechelus Lake Teanaway River

Umtanum Creek

Little Naches River

Cowichee Creek

Cowichee Creek

River

Naches

RIVER

YAKIMA

RIVER

YAKIMA

COLUMBIA 

RIVER

COLUMBIA RIVER

So. Fork

No. Fork

Cle Elum

Parker

Wapato

Ellensburg

Umtanum

Kittitas Thrall

Toppenish

Moxee

City Union Gap

Yakima

Selah

Naches

Sunnyside

Richland

Kiona

Kennewick

Prosser

Grandview

Mabton

Satus

Zillah

Granger

Roza

Easton

Teanaway

Tieton Rimrock

0 5 10 20 30 MILES

0 5 10 20 30 KILOMETERS

EXPLANATION

Sedimentary Basin boundary

Surficial hydrogeologic units

Basin-fill deposits

Quaternary Volcanic

Columbia River Basalt Group

Older bedrock

WASHINGTON

Extended

study area

Base from U.S. Geological Survey and (or) Washington Division

of Geology and Earth Resources digital data, 1983, 1:100,000

Universal Transverse Mercator projection, Zone 10

Horizontal Datum: North American Datum of 1927 (NAD 27)

Vertical Datum: North American Vertical Datum of 1988 (NAVD 88)

Moxee

Ahtanum

Syncline

Toppenish Ridge

Wahluke Syncline

Cold Creek Syncline

Kittitas Valley Syncline

Naneum Ridge Anticline

Manastash Anticline

Umtanum Anticline

Horse Heaven Hills Structure

Ainsley Canyon Anticline

Laurel Hill Monocline

Taneum Monocline

Cleman Mtn. Anticline

Ahtanum Ridge

Wapato Syncline

Wenas Syncline

 Rattlesnake Hills 

Structure

Yakima Ridge

Hog

Ranch Structure

Medicine Valley Syncline

Wilson Creek Monocline

Reeser Canyon

Monocline

Naneum Creek

Monocline

T.

24

N.

T.

22

N.

T.

20

N.

T.

18

N.

T.

16

N.

T.

14

N.

T.

12

N.

T.

10

N.

T.

8

N.

T.

6

N.

R.10E. R.12E. R.14E. R.16E. R.18E. R.20E. R.22E. R.24E. R.26E. R.28E.

121°

47°

47°

30'

46°

121°30' 120°30' 120° 119°30'

46°

30'

Figure 8. Extent of surficial hydrogeologic units, Yakima River basin aquifer system, Washington.
20 Hydrogeologic Framework of the Yakima River Basin Aquifer System, Washington

Hydraulic Characteristics of Units

The ability of sediments and rocks to store and transmit 

groundwater (their hydraulic characteristics) determines 

how a groundwater-flow system functions. Knowledge of 

the hydraulic characteristics also is necessary to evaluate 

how the flow system responds to stresses such as pumpage. 

These characteristics include lateral and vertical hydraulic 

conductivity and the storage coefficient. Estimates of 

characteristics from previous studies and this study are 

described below by categories of hydrogeologic units. 

Information described below provides a general overview of 

the range and median of hydraulic characteristic values for the 

hydrogeologic units.

Lateral Hydraulic Conductivity

Lateral hydraulic conductivity (referred to here as Kh) is 

a measure of a material’s ability to transmit water laterally. It 

is expressed in units of cubic feet per square feet per day—

simplified to feet per day (ft/d). Values of Kh can be estimated 

from specific-capacity data reported on drillers’ logs, or 

determined from aquifer tests or groundwater flow modeling. 

Numerous studies conducted in the Yakima River basin or in 

the surrounding area have calculated or compiled information 

on Kh (table 3). 

Basin-Fill Units

Basin-fill deposits are diverse in lithology and, thus, 

so are their hydraulic characteristics (table 3). The deposits, 

which consist of unconsolidated and consolidated material 

of fluvial, glacial, lacustrine, and volcanic origins, form 

important water-bearing units, as well as semiconfining to 

confining units. Estimates of effective Kh for the complete 

thickness of the basin-fill deposits ranged from 0.02 to 

150,000 ft/d. This large range in estimated values is due to the 

large variation in grain size, depositional regimes, and age of 

the deposits. The deposits include shale, sandstone, clay, sand, 

gravel, and cobbles.

The median reported values were in the range of 40 to 

240 ft/d. Kh of loess, which mantels part of the study area, is 

between 1 to 10 ft/d. The Touchet Beds, which also mantel 

part of the study area, have estimated Kh values between 8 

and 11 ft/d. Values of Kh for the alluvium range from 6 to 

100,000 ft/d and generally average between 100 and 800 ft/d. 

The large range is due to the variation in grain size (silty 

sands to cobbles) of the alluvium. In turn, grain-size varies 

complexly throughout the area. 

Estimates of Kh for the Pasco gravels that occur in the 

Eastern Benton basin ranges from about 48 to 73,000 ft/d, 

with a median reported value from about 880 to 1,250 ft/d. 

The reported values for the upper, middle, lower, and basal 

Ringold Formation range over several orders of magnitude, 

which reflects the wide-range in local conditions. Effective 

median values range from about 0.1 to 25 ft/d for the upper 

Ringold, from about 40 to 250 ft/d for the middle Ringold, and 

from about 0.1 to 4 ft/d for the lower Ringold; the median Kh

for the basal Ringold is about 200 ft/d.

Kh of the water-producing parts of the Ellensburg 

Formation ranges from about 0.01 to 2,265 ft/d. Average 

values reported for the Ellensburg range from about 0.1 to 

72 ft/d. The large range in the average values is due to the 

variations in the types of materials composing the waterproducing zones in the Ellensburg Formation. These materials 

range from sandstone to uncemented sands and gravels.

No information is available on the Kh of the claystone or 

clay sections of the Ellensburg Formation but Neuzil (1994) 

indicates that values may be as small as 10-7 to 10-4 ft/d. 

Neuzil (1994) also indicates that typical values of Kh for shale, 

which is present in parts of the Ellensburg Formation, is on the 

order of 10-8 to 10-7 ft/d.

Columbia River Basalt Group Units

Hydraulic characteristics vary greatly within and between 

the individual basalt flows, members, and hydrogeologic 

units (table 3). Upper zones of the flows were exposed to 

weathering processes and were broken by subsequent flows, 

resulting in the formation of conductive “flow tops.” These 

flow tops, when combined with the base of the overlying 

basalt flow, form interflow zones that generally exhibit high 

Kh (Lindolm and Vaccaro, 1988). In general, the flow tops are 

brecciated and (or) vesicular and the flow bases are brecciated 

and may contain pillow complexes if the basalt was extruded 

within or flowed into water. The interflow zones are separated 

by the less transmissive entablature and colonnade in which 

the fractures are typically vertically oriented (Tomkeieff, 

1940; Waters, 1960; MacDonald, 1967; Swanson and Wright, 

1978; Sublette, 1986; Hansen and others, 1994; Whiteman 

and others, 1994). The fractures are a result of differential 

contraction during cooling of basalt flows (MacDonald, 1967; 

Long and Wood, 1986) and of later folding and faulting. The 

greatest density and lowest Kh generally occur in the interior 

or middle of a basalt flow, typically the entablature (Wood 

and Fernandez, 1988; Reidel and others, 2002). Observations 

of exposed colonnades, which typically are three- to eightsided columns of basalt, suggest that there would be lateral 

connectivity along the columns; springs have been observed 

emanating from exposed colonnades. Many of the physical 

characteristics of the CRBG described above are similar to 

those of the Snake River Group (Lindolm, 1996), but Kh is 

much higher for the Snake River Group because the older 

CRBG flows have been affected by fracture filling with 

mineral precipitates (such as smectite and clinoptilolite) that 

decreases Kh (Wood and Fernandez, 1988; Steinkampf and 

Hearn, 1996). Fractures tend to be filled with these alteration 

products, whereas vesicles typically are only partly filled 

(Steinkampf and Hearn, 1996). Such alteration products are 

well documented (Ames, 1980; Benson and Teague, 1982; 

Hearn and others, 1985; Steinkampf and Hearn, 1996).
Hydraulic Characteristics of Units

21

Table 3. Summary of previous estimates of lateral hydraulic conductivity, Yakima River basin aquifer system, Washington.[Abbreviations: ft, foot; –, not applicable; >, greater than]

Unit or deposit Basin or area

Lateral hydraulic conductivity, in feet per day

 Source

Minimum Median Mean Maximum Model derived

Alluvium Toppenish 95.0 – – 778 – Bolke and Skrivan, 1981

Ahtanum-Moxee – – – – 284 Golder Associates, 2002Pasco/Benton 10 – 275 1,000 – Zimmerman, 1983

Alluvium, fluvial gravels, coarse sands Hanford 6 – – 100,000 – Vermeul and others, 2001Alluvium, coarse to medium grained 

(some fines and caliche)

Hanford/Black Rock – – .85 – – Didricksen, 2004

Alluvium, unconfined Ellensburg – – 2,000 – – GeoEngineers, 1999Alluvium, unconsolidated Ahtanum Valley 668 – 13 802 – Foxworthy, 1962Alluvium, young Lower Satus Creek – – – – 864 Prych, 1983Alluvium/Ellensburg (upper) Ahtanum-Moxee – – – – 75 Golder Associates, 2002Alluvium, old Lower Satus Creek – – – – 86 Prych, 1983Overburden aquifer Columbia Plateau .04 43 99 1,100 – Hansen and others, 1994

Columbia Plateau .02 240 – 150,000 – Whiteman and others, 1994

Loess Columbia Plateau – – – – 5 Lum and others, 1990

Columbia Plateau 1 – – 10 – Vaccaro, 1999

Plio-Pleistocene Unit Hanford .02 – – 57 – Khaleel and Freeman, 1995Sediments Horse Heaven Hills – – 24,192 – – Davies-Smith and others, 1989

Ellensburg, upper (old Alluvium) Lower Satus Creek .9 72 – 3,024 – Prych, 1983Ellensburg, upper Ellensburg 2 – – – 53 GeoEngineers, 1999Ellensburg, upper (all) Ahtanum-Moxee .6 – 13 2,265 – Golder Associates, 2002Ellensburg, upper (upper) Ahtanum-Moxee – – – – 7.5 Golder Associates, 2002Ellensburg, upper (upper 300 feet) Ellensburg – – – – 32 GeoEngineers, 1999Ellensburg, upper (upper and middle) Ahtanum-Moxee .6 – 12 2,265 – Golder Associates, 2002Ellensburg, upper (middle) Ahtanum-Moxee – – – – .002 Golder Associates, 2002Ellensburg, upper (lower) Ahtanum-Moxee 38 – 60 96 – Golder Associates, 2002

Ahtanum-Moxee – – – – 8 Golder Associates, 2002Ahtanum-Moxee – – – – .1 Golder Associates, 2002Ahtanum-Moxee – – – – .01 Golder Associates, 2002

Touchet beds Pasco/Benton 8 – – 11 9 Drost and others, 1997

Soil buried horizon, caliche, gravel Hanford 47 – – 625 – Vermeul and others, 2001Soils, Palouse Hanford .2 – – .4 – Khaleel and Freeman, 1995
22 Hydrogeologic Framework of the Yakima River Basin Aquifer System, Washington Unit or deposit Basin or area Lateral hydraulic conductivity, in feet per day Source Minimum Median Mean Maximum Model derived Pasco gravel Pasco/Benton 48 880 – 73,000 880 Drost and others, 1997 Pasco/Benton – 1,250 – – – Meyers and others, 1985 Hanford Formation Hanford 3 – – 3,281,000 – Wurstner and others (1995): Thorne and Newcomer (1992) Ringold Hanford/Black Rock – 2.6 – – – Didricksen, 2004 Ringold, upper Pasco/Benton 2 25 – 210 5 Drost and others, 1997 Hanford – – – – .02 Vermeul and others, 2001 Hanford .001 – – .3 – Wurstner and others (1995); Thorne and Newcomer (1992) Ringold, middle Pasco/Benton 200 – – 250 – Bergeron and others, 1986 Pasco/Benton 8 180 – 5,000 200 Drost and others, 1997 Pasco/Benton – 41 – – – Newcomb and others (1972); Graham (1981); Meyers and others (1985) Hanford .1 – – 5,500 – Vermeul and others, 2001 Hanford .03 – – 281 – Vermeul and others, 2001 Hanford .03 – – .3 – Vermeul and others, 2001 Hanford .3 – – 656 – Wurstner and others (1995); Thorne and Newcomer (1992) Hanford .001 – – .3 – Wurstner and others (1995); Thorne and Newcomer (1992) Hanford .3 – – 656 – Wurstner and others (1995); Thorne 

and Newcomer (1992)

Ringold, middle, gravel facies Hanford 2,000 – – 6,400 – Vermeul and others, 2003Ringold, middle, sand facies Hanford – – 1,300 – – Vermeul and others, 2003Ringold, middle, silt facies Hanford – – 2 – – Vermeul and others, 2003Ringold, lower Pasco/Benton 2 46 – 230 4 Drost and others, 1997

Hanford .001 – – .3 – Wurstner and others (1995); Thorne 

and Newcomer (1992)

Ringold, lower, basal, clay/mud Hanford – – – – .00003 Vermeul and others, 2001Ringold, basal Pasco/Benton 200 – – 250 – Bergeron and others, 1986

Hanford .3 – – 656 – Wurstner and others (1995); Thorne 

and Newcomer (1992)

Table 3. Summary of previous estimates of lateral hydraulic conductivity, Yakima River basin aquifer system, Washington.—Continued[Abbreviations: ft, foot; –, not applicable; >, greater than]
Hydraulic Characteristics of Units

23

Unit or deposit Basin or area

Lateral hydraulic conductivity, in feet per day

 Source

Minimum Median Mean Maximum Model derived

Ringold, basal, sand/gravel Hanford 0.03 – – 700 – Vermeul and others, 2001Rattlesnake Ridge Interbed Hanford/Black Rock – – 0.80 – – Didricksen, 2004

Hanford .05 – 8.4 210 – Strait and Mercer, 1987

Selah Interbed Hanford/Black Rock – – 2.7 – – Didricksen, 2004Saddle Mountains Horse Heaven Hills – – 18 – – Davies-Smith and others, 1988

Pasco/Benton .007 2 – 3,200 – Drost and others, 1997Columbia Plateau .2 1 1 3 – Hansen and others, 1994Columbia Plateau .007 2 – 1,892 – Whiteman and others, 1994Pasco/Benton – – – – 1 Zimmerman, 1983Hanford/Black Rock .04 – – 2.6 – Didricksen, 2004Hanford .04 2 10 53 – Schmidt and others, 2007

Saddle Mountains anticline Horse Heaven Hills .03 – – .5 – Packard and others, 1996

Horse Heaven Hills .2 – – 78 – Packard and others, 1996

Mabton Interbed Hanford/Black Rock – – .025 – – Didricksen, 2004Wanapum Horse Heaven Hills – – 170 – – Davies-Smith and others, 1988

Pasco/Benton 1.1 11 – 310 – Drost and others, 1997

Columbia Plateau .9 – – 1 – Lum and others, 1990

Columbia Plateau .09 3 3 8 – Hansen and others, 1994Horse Heaven Hills .1 – – 259 – Packard and others, 1996Columbia Plateau .007 5 – 5,244 – Whiteman and others, 1994Pasco/Benton – – – – 5 Zimmerman, 1983

Wanapum, interflow Hanford – 2.8 – – – Reidel and others, 2002Wanapum, flow interior Hanford – .000003 – – – Spane and Thorne, 1985Grande Ronde Horse Heaven Hills – – 65 – – Davies-Smith and others, 1988

Columbia Plateau 1 – – 12 – Lum and others, 1990Columbia Plateau .005 5 – 5,222 – Whiteman and others, 1994Pasco/Benton – – – – .02 Zimmerman, 1983

Grande Ronde, top Hanford .000003 0.1 – 500 – Strait and Mercer, 1987Grande Ronde, 1–2,000 ft thick Columbia Plateau .1 1 2 9 – Hansen and others, 1994Grande Ronde, flow interior Hanford 5×10-9 .0000002 – .001 – Strait and Mercer, 1987

Hanford 1×10-8 .00000014 – .000017 – Eslinger, 1986

Table 3. Summary of previous estimates of lateral hydraulic conductivity, Yakima River basin aquifer system, Washington.—Continued[Abbreviations: ft, foot; –, not applicable; >, greater than]
24 Hydrogeologic Framework of the Yakima River Basin Aquifer System, Washington Unit or deposit Basin or area Lateral hydraulic conductivity, in feet per day Source Minimum Median Mean Maximum Model derived Grande Ronde, interflow Hanford – 0.03 – – – Reidel and others, 2002 Grande Ronde, > 2,000 ft thick Columbia Plateau 0.1 1 2 6 – Hansen and others, 1994 Basalt Ahtanum-Moxee – – – – 5 Golder Associates, 2002 Columbia Plateau .9 – – 9 – Bolke and Vaccaro, 1981 Columbia Plateau .005 5 – 6,100 – Whiteman and others, 1994 Basalt, top Pasco/Benton – 35 – – – Drost and others, 1997 Basalt, center Pasco/Benton – .0000002 – – – Drost and others, 1997 Basalt, interflow Hanford .0000003 – – 2,800 – Reidel and others, 2002 Basalt, flow interior Hanford 3×10-10 .0000003 – .003 – Reidel and others, 2002 Basalt, weathered Ahtanum-Moxee – – – – .003 Golder Associates, 2002 Basalt, undisturbed Pasco/Benton .03 – – 8 – Zimmerman, 1983 Basalt, anticline Pasco/Benton .004 – – .3 – Zimmerman, 1983 Basalt, fault Pasco/Benton .0001 – – .01 – Zimmerman, 1983 Basalt, barrier (flow impediment) Pasco/Benton .002 – – .05 – Zimmerman, 1983 Bedrock, crystalline General .000003 – – .3 – Trainer, 1988 Bedrock, unfractured metamorphic and igneous rocks General .00000003 – – .00003 – Freeze and Cherry, 1979 Table 3. Summary of previous estimates of lateral hydraulic conductivity, Yakima River basin aquifer system, Washington.—Continued

[Abbreviations: ft, foot; –, not applicable; >, greater than]
Hydraulic Characteristics of Units 25

The Saddle Mountains Kh has been estimated to range 

from 0.007 to 3,200 ft/d, but results from previous studies 

indicate that the median is about 1 to 2 ft/d. The Wanapum had 

a slightly larger range (0.007 to 5,244 ft/d) than the Saddle 

Mountains, and the median reported Kh for the Wanapum 

ranges from about 3 to 11 ft/d. The range in Grande Ronde 

Kh values was similar to that for the Wanapum, from 0.005 to 

5,222 ft/d. Median values for the Grande Ronde range from 

about 0.1 to 5 ft/d. Previous work indicates the CRBG Kh is 

one to two orders of magnitude smaller along anticlines and 

in deeper parts of the Grande Ronde (Hansen and others, 

1994; Packard and others, 1996; Reidel and others, 2002) 

than in other parts of the units due to overburden pressure and 

secondary mineralization. For anticlines, Hansen and others 

(1994) reduced Kh values by multiplying the values by factors 

ranging from 0.01 to 0.018. For all types of flow barriers, the 

median multiplication factor was 0.18 (Hansen and others, 

1994). 

Strait and Mercer (1987) found Kh in basalt flow tops 

to be as much as five orders of magnitude greater than in 

basalt flow centers. Poeter (1980) reported that representative 

effective porosities ranged from about 0.02 in the flow 

interiors to about 0.14 in the interflow zones, further indicating 

the difference between Kh in interflow zones and flow 

interiors. Based on the median Kh values for the CRBG units 

as a whole (described above), assuming that about 10 percent 

of a unit consists of interflow zones, and using a depthweighted average yields a Kh for interflow zones of about 

10 to 100 ft/d. If the interflow zones comprised 5 percent 

of a unit then those estimates would double (20–200 ft/d). 

Hydraulic testing of interbeds in the basalts has been limited, 

but reported values range from 0.05 to 210 ft/d and appear to 

average between about 0.1 and 8 ft/d.

Bedrock Units

The headwater areas of the Yakima River basin in the 

Cascade geologic province include metamorphic (crystalline), 

sedimentary, volcanic, and intrusive and extrusive igneous 

rocks (table 2). Relatively little groundwater development of 

the bedrock units has occurred and therefore, little is known 

about their hydraulic characteristics. In general, the older, 

plutonic, metamorphic, volcanic, and sedimentary bedrock 

units have lower values of porosity and permeability than 

the basin-fill and CRBG units. Water-producing zones are 

variable, but are present in the bedrock units. 

Typical values of Kh for unfractured metamorphic and 

igneous rocks range from 3×10-8 to 3×10-5 ft/d (Freeze and 

Cherry, 1979). Kh values for fractured metamorphic and 

igneous rocks can be five orders of magnitude larger than 

for unfractured rock (about 0.001–1 ft/d). Joints within 

crystalline rock are of limited lateral extent but are numerous 

enough to increase permeability locally, and such fractures are 

commonly tighter and less abundant with increasing depth due 

to the state of stress in the earth’s crust (Trainer, 1988). The 

latter conditions may be important in the study area because 

of the existing tectonic stress that would tend to decrease 

fracture openings. Previous studies of well yields in crystalline 

rocks suggest networks of open joints are found principally 

within 300–500 ft of the surface and decline lognormally with 

increasing depth (Trainer, 1988). Trainer also reported that 

Kh valuesfor crystalline rocks range from 3x10-6 to 0.3 ft/d. 

Thus, Kh of the Paleozoic and Mesozoic units (predominantly 

metamorphic rocks—gneiss, schist, phyllite, and amphibolite) 

likely is quite small; many well yields are reported on driller’s 

logs as less than 1 gal/min or ‘no water.’

The older sandstone and basalt parts of the Tertiary 

units generally yield less water than most of the sandstone of 

the Ellensburg Formation and the basalt of the CRBG units. 

Similar to the well yields in the Paleozoic and Mesozoic units, 

many yields for the sandstone and basalts also are reported 

on driller’s logs as less than 1 gal/min or ‘no water.’ For the 

sandstone, proximity to the Cascade uplift and volcanism may 

have reduced pore space through heating, resulting in reduced 

Kh values. For the older basalts, tectonic stress and secondary 

mineralization also may account for reduced Kh values. Thus, 

on the basis of information for the CRBG and the Ellensburg 

Formation, and values in Freeze and Cherry (1979), Kh for the 

sandstone and basalt are likely on the order of 0.001 to 1 ft/d.

Few wells are completed in the Quaternary bedrock 

unit to assess its Kh values. The unit probably is permeable, 

however, based on information for similar rock types of 

similar ages, for example, the Quaternary basalts of the 

eastern Snake River Plain aquifer system. The Snake River 

basalts have Kh values ranging from 1 to more than 7,000 

ft/d (Garabedian, 1986; Lindolm, 1996). A smaller range in 

values, typically from 1 to 20 ft/d, for the Quaternary basalts 

in Oregon has been estimated by Ingebritsen and others (1992) 

and Manga (1996, 1997). 

Estimates from Specific-Capacity Data

Lateral hydraulic conductivities were estimated as part 

of this study using available data for water-level change 

(drawdown) and discharge rate (well yield) for wells pumped 

for periods that ranged from less than 1 hour to 200 hours. 

Data from wells that had a driller’s log containing a discharge 

rate, duration of pumping, drawdown, static water level, 

well-construction data, and lithologic log were used. The 

methods and assumptions for calculating Kh are described in 

appendix A. Assumptions for calculating Kh from specificcapacity data generally are not strictly met resulting in values 

that may be considered rough estimates. Spatial variations 

can provide indications of patterns of Kh, however, and the 

availability of many values allows for a reasonable estimate of 

a median value. The limitations of using specific-capacity tests 

are described by Gannett and Lite (2004) and Meier and others 

(1999). 
26 Hydrogeologic Framework of the Yakima River Basin Aquifer System, Washington

Snoqualmie

Pass

Van Epps 

Pass 

Esmeralda

Peaks

K I T T I T A S

V A L L E Y

M A N A S T A S H

KACHESS RIDGE

R I D G E

UNION GAP

CLEMAN 

MOUNTAIN 

TEANAWAY

NORTH RIDGE

U M T A N U M

R I D G E

Deception

Pass

Y A K I M A 

 V A L L E Y 

AHTANUM RIDGE

COWICHE MTN

AMERICAN RIDGE

CLE ELUM

RIDGE

RIDGE

TOPPENISH RIDGE

R A T T L E S N A K E H I L L S

Y A K I M A R I D G E

H O R S E

H E A V E N

H I L L S

C

A

S C A

D E R

A

N

G

E

W E N AT C H E E

M O U N TA I N S

Gilbert

Peak

0 5 10 20 30 40 MILES

0 5 10 20 30 40 KILOMETERS

EXPLANATION

Basin-fill deposits

Columbia River Basalt Group

Bedrock

Well yield, in gallons per minute

0 to 5

6 to 50

51 to 500

501 to 1,000

1,001 to 3,724

0 to 5

6 to 50

51 to 500

501 to 1,000

1,001 to 4,200

0 to 5

6 to 50

51 to 300

Roslyn

Kittitas

Selah

Yakima

Extended Toppenish

Eastern Benton

Basins

Cle Elum

Parker

Wapato

Ellensburg

Umtanum

Kittitas

Thrall

Toppenish

Moxee City

Union Gap

Yakima

Selah

Naches

Sunnyside Richland

Kiona

Kennewick

Prosser

Grandview

Mabton

Satus

Zillah

Granger

Roza

Easton

Teanaway

Tieton Rimrock

Base from U.S. Geological Survey and/or

Washington Division of Geology and Earth Resources

digital data, 1983, 1:100,000

Universal Transverse Mercator projection, Zone 10

Horizontal Datum: North American Datum of 1927 (NAD 27)

Bumping

Lake

S Fk 

N Fk 

Cle Elum River

Bumping River

Ahtanum Creek

Tieton River

Wenas Creek

North Fork

Dry Creek

Creek

Toppenish

RIVER

YAKIMA

Satus

Creek

Cle

Elum

Lake

Rimrock 

Lake 

Kachess Lake 

Keechelus Lake 

Lake 

Wallula 

Teanaway River

Umtanum Creek

Little Naches River

Cowiche Creek

River Naches

RIVER

YAKIMA

RIVER

YAKIMA

N. Fork.

 S. Fork Cowiche Creek

T.

24

N.

T.

22

N.

T.

20

N.

T.

18

N.

T.

16

N.

T.

14

N.

T.

12

N.

T.

10

N.

T.

8

N.

T.

6

N.

R.10E. R.12E. R.14E. R.16E. R.18E. R.20E. R.22E. R.24E. R.26E. R.28E.

121°

47°

47°

30'

46°

121°30' 120°30' 120° 119°30'

46°

30'

Figure 9. Reported yields of wells, Yakima River basin aquifer system, Washington.

 Well-yield data are needed not only to estimate Kh but 

also to improve the understanding of the potential productivity 

of a hydrogeologic unit. Available data indicate that yields in 

the bedrock units generally are about an order of magnitude 

smaller than those in the basin-fill and CRBG units (fig. 9). 

The average yield per foot of total well depth for the bedrock, 

CRBG, and basin-fill units was 0.1, 0.9, and 2.8 (gal/min)/ft, 

respectively. The largest yields in the basin-fill sediments 

and CRBG are found along the boundaries of the Yakima, 

Toppenish, and Benton basins. Most of the wells with large 

yields are irrigation wells and secondarily, municipal wells, 

because the well depth, well diameter, and number of waterproducing zones are optimized to meet the large water 

demands of irrigation and public supply. 
Hydraulic Characteristics of Units 27

Statistical summaries of Kh values calculated from the 

specific-capacity data, by hydrogeologic unit, are shown in 

table 4. The median values are similar in magnitude to values 

reported by Freeze and Cherry (1979) for similar materials and 

to values described previously. The information in table 4 also 

indicates that, overall, the values for the basin-fill and CRBG 

units are similar. Note that the bedrock values are based on a 

limited number of tests, and data for wells identified as ‘dry’ 

or little production were not included, resulting in a likely 

bias to larger values. In addition, bedrock values were not 

separated by hydrogeologic unit and different bedrock types 

have different effective Kh values. For example, the phyllite 

rocks of the Mesozoic unit are known to exhibit very low 

Kh, with well yields generally less than 1–2 gal/min. The 

minimum values illustrate that zones of low Kh are present 

in most units, and the large range in Kh (fig. 10) indicates 

substantial heterogeneity in the units.

0

5

10

15

20

25

30

35

-5 to -4

-4 to -3

-3 to -2

-2 to -1

-1 to 0

0 to 1

1 to 2

2 to 3

3 to 4

4 to 5

5 to 6

6 to 7

7 to 8

8 to 9

9 to 10

10 to 11

HYDRAULIC CONDUCTIVITY, IN LOGARITHM (BASE E) OF FEET PER DAY

FREQUENCY OF OCCURRENCE, IN PERCENT 

Basin-fill deposits

Columbia River Basalt Group

Bedrock

Table 4. Summary of lateral hydraulic conductivity values, estimated from specific-capacity data, Yakima River basin aquifer system, 

Washington.

Hydrogeologic unit Number of 

wells

Hydraulic conductivity, in feet per day

Mean Median Minimum 25th

percentile

75th

percentile Maximum

Basin-fill units 882 182 6 0.01 0.4 49 17,715

Columbia River Basalt Group units 833 182 3 .1 .4 25 48,787

Bedrock units 9 13 3 .01 .3 33 40

Figure 10. Frequency distribution of lateral hydraulic conductivity values estimated from specific-capacity data, Yakima River 

basin aquifer system, Washington.
28 Hydrogeologic Framework of the Yakima River Basin Aquifer System, Washington

Figure 11. Distribution of lateral hydraulic 

conductivity estimated from aquifer test data, Yakima 

River basin aquifer system, Washington.

wa19-0148_fig11-Lateral Hyrdo Conduct estimate

90th percentile

EXPLANATION

10th percentile

75th

25th

50th (median)

0

1

10

100

1,000

BASIN-FILL

DEPOSITS

COLUMBIA RIVER

LATERAL HYDRAULIC CONDUCTIVITY, IN FEET PER DAY

BASALT GROUP

599

76

3

1

132

25

7

2

26

7

Estimates from Aquifer Tests

Kh values were calculated using 

aquifer-test data for 99 wells (49 basinfill wells and 50 CRBG wells). In all 

tests, drawdowns were for the pumping 

well. Calculations were made using 

the Cooper-Jacob time-drawdown 

(Cooper and Jacob, 1946), and Theis 

and Theis recovery (Theis, 1935) 

(see also Bentall, 1963) methods. All 

methods have certain assumptions, 

many of which are not strictly met. 

The full theoretical background of each 

method, including assumptions and 

limitations, can be found in the original 

documentation.

The mean and median Kh values 

for the basin-fill units were 167 and 26 

ft/d, respectively, and for CRBG units 

they were 36 and 7 ft/d, respectively. 

Box plots of the calculated values 

(fig. 11) show much narrower ranges 

than values calculated from specificcapacity data, although the CRBG 

median value is similar to both the median of the specificcapacity derived value and previously reported values. For the 

basin-fill deposits, the diversity in lithology results in a larger 

difference in the median value between the methods. For 

example, some specific-capacity data are for coarse-grained 

materials such as cobbles, whereas others are from less 

productive sandstone; most of the aquifer test data, however, 

are for high-yield irrigation wells completed in coarse-grained 

material.

Vertical Hydraulic Conductivity

Vertical hydraulic conductivity (Kv) is an important 

hydraulic characteristic that is difficult to determine. It is a 

measure of a material’s ability to transmit water vertically 

(the impedance to downward/upward flow) and is expressed 

in units of feet per day. Kv is a major control on the movement 

of water in the flow system—lateral and vertical variations in 

Kv affect vertical hydraulic gradients, and therefore, flow rates 

into, within, and out of units. Except for the work of Drost 

and others (1997), who used measured canal seepage rates to 

calculate Kv, nearly all of the previous estimates of Kv were 

derived using groundwater flow models.

Basin-Fill Units

The large differences in the types of basin-fill units 

results in a large variation in estimates of Kv. Fine-grained 

units, such as shale and clay, have values as small as 10-10

to 10-6 ft/d. Kv values between about 10-3 to 10-2 ft/d were 

estimated for units that contain fine-grained material such as 

loess and parts of the Ringold Formation. In contrast, more 

coarse-grained units had estimated values ranging from about 

10-1 to 10 ft/d. Overall, Kv values ranged from 10-7 to 12 ft/d.

Bolke and Skrivan (1981) assigned a constant Kv of 

9 × 10-3 ft/d in a groundwater model of the Toppenish alluvial 

aquifer. For the lower Satus Creek basin, Prych (1983) 

assumed a Kh:Kv anisotropy ratio of 1,000:1 for the old 

alluvium and upper Ellensburg Formation, yielding a Kv of 

0.09 ft/d in a groundwater model. For the Touchet Beds in the 

lower Satus Creek basin, Prych’s (1983) estimate of Kv ranged 

from 0.1 to 12 ft/d. On the basis of the previously described Kh

values, effective regional Kv values for the basin-fill units are 

likely on the order of 0.1 to 1 ft/d.

For the sedimentary material overlying the Saddle 

Mountain unit in the Eastern Benton basin, Zimmerman 

(1983) assumed Kv to be controlled by the clays of the Ringold 

Formation, and used a constant value of 9 × 10-3 ft/d in a 

groundwater flow model.

Smoot and Ralston (1987) and Lum and others (1990) 

estimated a value of 0.05 ft/d for loess on the basis of a 

vertical anisotropy of 100:1. Hansen and others (1994) 

estimated Kv ranging from 4 × 10-7 to almost 1,400 ft/d for the 

sediments overlying the CRBG; the median value was 2 ft/d 

and the average vertical anisotropy was 25:1.

Drost and others (1997) used irrigation canal-seepage 

rates to estimate Kv in the Pasco basin. This method resulted 

in values of 0.4, 0.7, and 0.4 ft/d for the Touchet Beds, Pasco 

gravels, and upper Ringold Formation, respectively.
Hydraulic Characteristics of Units 29

The Kv of the fine-grained (such as claystone, mudstone, 

and shale) parts of the consolidated units also is unknown 

but is likely as small as 10-10 to 10-6 ft/d assuming a Kh:Kv

ratio of 1,000:1. Bredehoeft and others (1983) estimated Kv of 

the Pierre Shale and Cretaceous shale in South Dakota to be 

about 4 × 10-6 and 0.0005 ft/d, respectively. They also noted 

that values greater than 4 × 10-6 for the thick Cretaceous shale 

would not support an underlying flowing-artesian aquifer 

system due to increased vertical leakage. That is, the known 

upward vertical leakage through the shale has a threshold 

that is limited by the value of Kv. For the thick upper part of 

the late-Cretaceous Hell Creek Formation (shale dominated) 

in Montana, Hotchkiss and Levings (1986) used aquifer test 

data to estimate a maximum range in Kv from 0.00005 to 

0.001 ft/d from aquifer tests. Model-derived Kv values for 

the shale-dominated confining units in a 42,000 mi2 area 

of eastern Montana and northeastern Wyoming were about 

0.00002 ft/d (Hotchkiss and Levings, 1986). Taken together, 

the summarized information indicates that the Kv of thick shale 

probably ranges from about 10-6 to 10-3 ft/d.

Columbia River Basalt Group Units

Zimmerman (1983) examined two possible controlling 

mechanisms of Kv for different basalt zones. In the “base 

case,” dense basalts were assumed to be the primary control 

on vertical flow. In the “alternate base case,” interbeds were 

the primary control. In both cases, dense basalts were assumed 

to control vertical flow in undisturbed zones. Zimmerman 

assigned vertical anisotropy ratios (Kh:Kv) of 1,000:1 to 

all groundwater model nodes in undisturbed zones, which 

yielded Kv values ranging from 3×10-5 to 8×10-5 ft/d. Fault 

and barrier zones for both cases were simulated as isotropic 

(Kh:Kv = 1), which may be similar to the anisotropy of a basalt 

flow interior. Differences between the two cases occurred 

along anticlines where interbeds rather than dense basalts 

were assumed to control vertical flow. Davies-Smith and 

others (1988) also estimated that the Mabton unit, in contrast 

to basalt, exerted more control on the vertical movement of 

water in the Umatilla basin in Oregon, where the Mabton 

is composed of fine-grained deposits. Vertical anisotropy 

for Saddle Mountains and Wanapum were assigned values 

of 8,333:1 and 2,063:1, respectively, yielding values for Kv 

ranging from 4×10-7 to 1.5×10-4 ft/d (Davies-Smith and others, 

1988).

Vertical anisotropy for the Wanapum was estimated to be 

500:1, with Kv ranging from 8.0×10-4 to 1.2×10-3 ft/d in the 

Pullman-Moscow basin in Washington and Idaho (Smoot and 

Ralston, 1987; Lum and others, 1990). These investigations 

estimated the Grande Ronde anisotropy to range from 2,000:1 

to 5,000:1, with Kv ranging from 1×10-4 to 2.5×10-3 ft/d.

Whiteman and others (1994) reported that Kv of the 

Columbia Plateau aquifer system was largely unknown, 

but estimated that values ranged from 5×10-4 to 4 ft/d, with 

vertical anisotropy of 1,000:1 to 100:1. Hansen and others 

(1994) estimated that Kv in the system ranged from 5×10-5

to 7 ft/d, with a median value of 1×10-3 ft/d. Typical vertical 

anisotropy was 1,500:1 to 1,000:1.

Packard and others (1996) estimated Kv for two zones 

(anticlines and synclines) in a groundwater flow model of the 

Horse Heaven Hills on the southeastern border of the basin. 

A Kv value of 5×10-4 ft/d was calibrated for the anticline 

zone for the Saddle Mountains and Wanapum, whereas along 

the synclines the average value was larger (0.01 ft/d). The 

anisotropy ratio for the Wanapum was similar to that of Lum 

and others (1990).

Drost and others (1997) estimated Kv to be 0.3 ft/d for 

the Saddle Mountains on the basis of canal seepage losses. 

Although this Kv is larger than most other reported values, it 

was based on water-level changes with time resulting from a 

known amount of seepage (recharge).

Bedrock Units

The authors have been unable to locate any previous 

estimates of Kv for the bedrock units in the study area. Kv

values for these units likely range over several orders of 

magnitude and vary by the type of materials comprising a unit, 

for example, schist in contrast to sandstone. For the Paleozoic, 

Mesozoic, and Tertiary units as a whole, the average vertical 

anisotropy would be large, perhaps on the order of 2,000:1 to 

10,000:1. On the basis of information described above, Kv for 

the shale/clay parts of the sedimentary units may range from 

4×10-6 to 0.0005 ft/d. 

Storage Coefficient

The storage coefficient is a measure of a unit’s ability 

to store and release water, and is defined as the volume of 

water that a unit will absorb or release from storage per unit 

surface area per unit change in head. It is expressed in units 

of cubic feet per cubic feet, a dimensionless quantity. Storage 

coefficients for a confined aquifer can range from 5×10-5 to 

0.005 and values for an unconfined aquifer (referred to as 

specific yield) are much larger, and can range from 0.01 to 

0.30 (Freeze and Cherry, 1979).

Analyses of aquifer tests in the Pasco basin yielded 

unconfined storage coefficient values of 0.1 for the middle 

Ringold Formation and 0.15 to 0.2 for Pasco gravels (Drost 

and others, 1997). Aquifer tests in the confined parts of 

the Pasco basin yielded storage coefficients of 0.03 to 0.07 

for Pasco gravels, 7×10-5 to 0.06 for the middle Ringold 

Formation, 0.002 to 0.05 for the lower Ringold Formation, 

and 1×10-6 to 0.006 for the CRBG (Drost and others, 1997). 

Drost and others, (1997) also reported that previous modeling 

studies calibrated CRBG storage coefficient values of 

0.0001 to 0.01. Vermeul and others (2001) estimated storage 

coefficients for the coarse-grained sediments of the unconfined 

parts of the Hanford and Ringold Formations as 0.07 and 

0.2, respectively. Model-derived storage coefficients for all 

confined units were 1×10-6.
30 Hydrogeologic Framework of the Yakima River Basin Aquifer System, Washington

On the basis of grain size, Drost and others (1997) 

estimated storage coefficients for the Touchet Beds (0.08), 

upper Ringold Formation (0.07 to 0.2), and lower Ringold 

Formation (0.02 to 0.2). Prych (1983) used a specific yield 

of 0.1 for the Touchet Beds in the lower Satus Creek basin. 

Specific yield for the Toppenish alluvial aquifer has been 

estimated to be 0.2 (U.S. Geological Survey, 1975). 

Golder Associates (2002) estimated a storage coefficient 

of 2×10-3 for the lower part of the upper Ellensburg Formation 

on the basis of buildup and drawdown data during aquifer 

tests. Converse Consultants NW (1991) used data from a 

24-hour aquifer test to estimate a storage coefficient of about 

7×10-4 for the lower part of the upper Ellensburg Formation.

Whiteman and others (1994) indirectly estimated 

storage coefficients for the CRBG units on the basis of 

specific storage. Median values for the Saddle Mountains, 

Wanapum, and Grande Ronde were 2×10-5, 3×10-5, and 

2×10-4, respectively. For the sediments overlying the CRBG, 

they estimated values ranging from 2×10-4 to 0.2.

Previously-estimated storage coefficients were initially 

used by Hansen and others (1994, table 4) in the Columbia 

Plateau aquifer system model. Model-derived specific 

yields for the overburden aquifer ranged from 0.1 to 0.2. 

The estimated median storage coefficients for the Saddle 

Mountains, Wanapum, and Grande Ronde were 4×10-5, 

4×10-5, and 2×10-4, respectively. Packard and others (1996) 

initially assigned CRBG storage coefficients on the basis of 

previous studies in a groundwater model of the Horse Heaven 

Hills. Transient calibration of the model yielded values of 

1×10-3 for the Grande Ronde and Wanapum and 1×10-2 for the 

Saddle Mountains.

Values of unconfined and confined storage coefficients for 

the sandstone layers of the bedrock units are unknown. Leake 

and others (2005) estimated values of 10-4 and 0.06 (confined 

and unconfined values, respectively) for the Permian Coconino 

Sandstone of the Coconino Plateau, Arizona. Wells completed 

in this sandstone generally yield about 1 gal/min, which is 

similar to many reported well yields from the sandstone in the 

bedrock units in the study area. Values for the basalt part of 

the bedrock units are likely smaller than those of the younger 

CRBG due to fracture infilling and may range from about 10-6

to 10-4. Values also are unknown for the Quaternary bedrock 

unit but should be similar to those reported for the Quaternary 

basalts of the Snake River Plain aquifer that has reported 

specific yield values of 0.01 to 0.20 and storage coefficient 

values of 10-5 to 10-3 (Lindolm, 1996).

Hydrochemistry

Patterns in the variations in the stable isotopes of 

hydrogen and oxygen, carbon isotopes, and concentrations of 

dissolved constituents, including methane and noble gases, can 

be used to infer information on the hydrogeologic framework 

and groundwater movement, including vertical movement 

of groundwater in both the CRBG units and the overlying 

basin-fill units. After recharge of isotopically distinct water, 

the extent of water-rock interaction increases with increased 

contact time and temperature, such that the concentrations of 

many dissolved constituents can either increase or decrease 

as groundwater flows from areas of groundwater recharge to 

areas of groundwater discharge. Dissolved chloride, fluoride, 

and helium are essentially non-reactive solutes in the dilute 

basaltic groundwater of the aquifer system. Thus, these 

constituents, along with sodium (because of its limited reactive 

character), tend to accumulate in groundwater along flow 

paths and are indicators of the extent of water-rock interaction. 

The concentration of other solutes, such as dissolved oxygen, 

carbon-14, and magnesium tend to decrease along flow paths. 

The concentration of dissolved inorganic carbon, which is a 

reactive component in groundwater in the aquifer system, also 

can be analyzed in conjunction with variations in carbon-13 

to provide additional information on the conceptual model of 

groundwater in the aquifer system.

Hydrochemical data available for analysis include data 

collected by the USGS during this study, unpublished data 

from the Toppenish basin previously collected by the Yakama 

Nation (appendix B), USGS data reported by Bortleson and 

Cox (1986), Steinkampf and Hearn (1996), and the National 

Water-Quality Assessment Program, and stored in NWIS, and 

data for the lower Pasco basin (in particular the Hanford Site) 

obtained by the U.S. Department of Energy (Early and others, 

1986; Reidel and others, 2002). All USGS data were collected 

using standardized USGS techniques and the water samples 

were analyzed by the methods of analysis of the USGS (for 

example, Fishman and Friedman, 1989, Brenton and Arnett, 

1993, and U.S. Geological Survey, 2006). Data reported 

by others also were collected and analyzed using published 

protocols and methods of analysis. Some of the hydrochemical 

data for the deeper basalt wells outside the Hanford Site were 

collected from large-capacity production wells with multiple 

contributing zones that provide suboptimum geochemical 

sampling conditions. However, the work of Hearn and others 

(1985), McKinley (1990), and Steinkampf and Hearn (1996) 

shows the value of those data in assessing the hydrogeologic 

framework, geochemical evolution of groundwater, and 

groundwater movement.
Hydrochemistry 31

Variation in Major-Ion Concentration

Concentrations of solutes in groundwater change with 

the residence time of the water and its flow path. Groundwater 

typically evolves from an oxygenated calcium-magnesiumbicarbonate type in recharge areas to an anoxic sodiumpotassium-bicarbonate type at deeper, downgradient locations. 

Long flow paths extending deeply into the central Pasco basin 

lead to anoxic groundwater of a sodium-chloride type (Reidel 

and others, 2002), the penultimate end-member water type 

along the deepest flow paths. 

The carbon present in the aquifer system is primarily 

in the bicarbonate form. Bicarbonate concentrations in 

recharge are a function of carbonic acid solution of carbon 

dioxide generated by soil respiration. Other dissolved 

solutes in basaltic groundwater are derived principally 

from the dissolution of basaltic glass and to a lesser extent 

plagioclase feldspar (Hearn and others, 1985). Chloride, 

sodium, and fluoride are essentially non-reactive solutes in 

basaltic groundwater of the Yakima River basin and tend to 

accumulate and provide information on the flow system. For 

example, information on sodium and chloride concentrations 

can be used to make rough estimates of residence times 

based on dissolution rates (Steinkampf and Hearn, 1996). 

Sodium and chloride concentrations greater than about 20 

and 5 mg/L, respectively, tend to be associated with higher 

concentrations of accumulated fluoride, indicating residence 

times greater than 5,000 years (Steinkampf and Hearn, 

1996). In turn, sodium concentrations in the CRBG units are 

significantly related to pH and further indicate evolution of the 

hydrochemistry along flow paths. A more detailed description 

of the chemical evolution of groundwater in the CRBG units 

can be found in Hearn and others (1985), Steinkampf and 

Hearn (1996), and Reidel and other (2002). 

Deuterium and Oxygen-18

The isotope ratios of hydrogen (2H/1H) and oxygen 

(18O/16O) are expressed in delta notation as δD and δ18O and 

are reported in units of per mil (or parts per thousand, ‰). The 

δD and δ18O in groundwater and surface water in the basin 

plot near the Global Meteoric Water Line (GMWL) of Craig 

(1961) (fig. 12A), as well as Local Meteoric Water Line for 

Washington State (Coplen and Kendall, 2000; Kendall and 

Coplen, 2001). The slope of the regression line fitted to all 

the groundwater and surface-water data is 7.8, which closely 

approximates the 8.0-slope of the GMWL. These data indicate 

that the source of groundwater in the Yakima River basin is 

meteoric water derived from atmospheric precipitation that is 

largely unaffected by evaporation. This finding is consistent 

with that of Hendry and others (1992). Small differences were 

observed in the slope of meteoric water lines for different 

hydrogeologic units and components of the hydrologic 

system, indicating local variability within the large regional 

system. The isotopic composition of precipitation is quite 

variable compared to groundwater and surface water (fig. 12B; 

Hendry and others, 1992). The larger variations in the isotopic 

composition of precipitation are related to differences in 

altitude and the seasonality of precipitation; these types of 

variations are common for precipitation (Gat, 1980; Clark 

and Fritz, 1997, Coplen and others, 2008). The slope of the 

precipitation meteoric water line is close to 7 (regression 

line and equation shown in fig. 12B), which is similar to the 

precipitation slope from the Hanford Site (Early and others, 

1986). 

Isotopic data for the alluvial aquifers (unconsolidated 

units) cluster in a narrow range, and are similar to the 

surface-water data (figs. 12C, D). Areas where surface-water 

recharge is a substantial fraction of groundwater recharge are 

evidenced by a shift in the δD and δ18O values. For example, 

infiltration of surface water from irrigation canal leakage and 

the application of surface water to croplands accounts for 

large quantities of local groundwater recharge (Vaccaro and 

Olsen, 2007a), and thus, the similarity in isotopic composition. 

The distribution of isotopic compositions of groundwater 

from alluvial aquifers overlaps those for the Yakima River 

samples, whereas isotopic compositions of groundwater from 

the consolidated (composed of the Ellensburg Formation) 

and CRBG units are typically more depleted in the heavier 

isotopes (more negative delta values) and more variable than 

the isotopic compositions for both the Yakima and Naches 

Rivers (figs. 12C, D). The δ18O of samples from the Yakima 

and Naches Rivers cluster between -12 to -14.5 ‰ and the 

δD ranges between -87 to -108 ‰. The groundwater samples 

with more negative delta values have a larger range, with 

δ18O ranging from -14 to -19.5 ‰ and δD ranging from -105 

to -145 ‰. Thus, substantial differences are apparent in 

the individual isotopic compositions of surface waters and 

their ranges compared to those of groundwater from most 

consolidated and CRBG units (figs. 12C, D). The δD and δ18O 

values (-135 and -16.2 ‰, respectively) reported for a deep 

(1,163 ft) Ellensburg Formation well in the Ahtanum subbasin 

(Golder Associates, 2001) are in this range and are similar to 

values for other deep wells (appendix B). The larger variation 

in the isotopic compositions of groundwater from consolidated 

and CRBG units as compared to surface water is indicative of 

a more extensive groundwater recharge area in the uplands but 

in some instances also may be related to cooler paleoclimatic 

conditions of the most recent glacial period (Larson and 

others, 2000). The difference in the isotopic compositions of 

water from the consolidated and CRBG units as compared 

to the alluvial (unconsolidated) units is clearly shown by the 

regression lines and equations of figure 12D.
32 Hydrogeologic Framework of the Yakima River Basin Aquifer System, Washington

wa19-0148_Fig.12a-d-stable iso comp -100 -110 -120 -130

-140-150

-70-80-90

-20 -18 -16 -14 -12 -10 -8

DEUTERIUM, IN PER MIL DEUTERIUM, IN PER MIL

DEUTERIUM, IN PER MIL DEUTERIUM, IN PER MIL

Stable isotopes and Global Meteoric Water Line

Surface Water

Regression equation

GMWLGroundwaterPrecipitation

-100-110-120-130-140-150

-70-80-90

-20 -18 -16 -14 -12 -10 -8

-100-110-120-130-140-150

-70-80-90

-20 -18 -16 -14 -12 -10 -8

-100-110-120-130-140-150

-70-80-90

-20 -18 -16 -14 -12 -10 -8

OXYGEN-18, IN PER MILOXYGEN-18, IN PER MIL

OXYGEN-18, IN PER MILOXYGEN-18, IN PER MIL

Yakima River at KionaYakima River at Cle ElumNaches River Yakima River at UmtanumYakima River at AhtanumYakima River at Euclid Bridge

Stable isotopes in precipitation collected at different altitudes in the Toppenish basin 

Stable isotopes in surface water

Stable isotopes in groundwater from the Toppenish basin 

A.B.

C.D.

Alluvium 2H = 8.9 18O + 22 

2H= 6.82 18O - 13.9

937

1,5002,0404,0855,720

2H = 7.3 18O - 8.3

Consolidated units

Basalt

2H = 8.2 18O + 0.4 

Regression equation

Altitude, in feet

Figure 12. Relation between stable isotopic composition (deuterium and oxygen-18) samples in (A) all water samples, (B) precipitation in the Toppenish basin, 

(C) surface water in the Yakima River basin, and (D) groundwater in the Toppenish basin, Washington.
Hydrochemistry 33

Methane

Dissolved methane has previously been reported in 

groundwater from semi-confined to confined aquifers in the 

CRBG (Hammer, 1934; Walsh and Lingley, 1991; Johnson and 

others, 1993; and Reidel and others, 2002). The concentration 

of dissolved methane measured in 80 percent of samples from 

consolidated and CRBG unit wells (appendix B) were larger 

than could be attributable to atmospheric sources; current 

atmospheric concentration of methane is about 1.2 mg/L. 

Concentrations as large as 50 mg/L were measured in samples 

analyzed by gas chromatography and actual concentrations 

may be larger because the gas-chromatography analysis of 

dissolved concentrations of nitrogen showed substantial 

alteration from atmospheric concentrations—indicting partial 

stripping of dissolved gases during sampling. 

The stable carbon isotopic compositions of carbon 

(δ13Cmethane; 13C/12C) of dissolved methane in groundwater 

varied from -9.9 to -53.0 ‰, with all but one value ranging 

between -32.7 to -53.0 ‰ (fig. 13). These values are typical 

of methane produced by thermocatalytic breakdown of higher 

mass hydrocarbons by heat (δ13Cmethane ranging from -25 to 

-50 ‰) as opposed to biogenic production (δ13Cmethane ranging 

from -50 to -80 ‰) of methane from microbial reduction of 

buried organic matter (Clark and Fritz, 1997). A biogenic 

source of dissolved methane could be produced within the 

consolidated and CRBG units by microbial methanogenesis, 

whereas thermocatalytic sources would indicate methane 

migration from outside the consolidated-CRBG part of the 

aquifer system. Microbial methanogenesis and oxidation 

would substantially influence the δ13CDIC isotopic ratio of 

dissolved inorganic carbon (DIC), which is also used to age 

date groundwater. According to Johnson and others (1993), the 

isotopic composition of methane present in groundwater on the 

Hanford Site, located at the terminus of regional groundwater 

flow paths, indicates that the source of the methane was 

a mixture of biogenic and thermogenic processes, and its 

occurrence in groundwater in the deeper CRBG units was 

largely due to entrainment by upwelling groundwater from 

coal beds in Tertiary sedimentary rocks underlying the CRBG. 

Biogenic methane also has been reported in groundwater from 

south-central Washington with δ13Cmethane values of -63.6 to 

-88.2 ‰ (Rice, 1993). These values are consistent with the 

fact that highly-reducing geochemical conditions necessary 

for methanogenesis are present in the groundwater system in 

the Yakima River basin (appendix B) and carbon, in the form 

of peat, is present in some areas of the Grande Ronde unit 

(Steinkampf and Hearn, 1996). 

The observed concentrations of methane are not 

uniformly distributed (fig. 13). For example, large 

concentrations of methane suitable for production of gas, 

such as in the Rattlesnake Hills Gas Field described by 

Hammer (1934), do not exist elsewhere in the basin. Several 

hydrocarbon exploration wells drilled through the Grande 

Ronde unit in eastern Washington, however, have been 

reported to have concentrations of methane approaching 

quantities necessary for commercial development. Johnson 

and others (1993) concluded that the areal distribution of 

methane in the CRBG on the Hanford Site is controlled 

by preferential flow near vertical faults. For example, 

major structural features such as the Cold Creek Fault have 

been cited as the source of the uneven vertical and lateral 

distribution of methane near a Hanford Site well (Reidel and 

others, 2002). However, most of the occurrences of methane 

measured in groundwater samples from wells outside of the 

Hanford Site were found at locations several miles distant 

from mapped structural fault features, indicating upward 

vertical movement of predominantly thermogenic methane 

from the underlying bedrock may be more widespread than 

previously thought and (or) the more general occurrence of 

unmapped fault structures. In either case, upward migration of 

methane through the CRBG from the underlying bedrock units 

is indicated by the data.

Carbon and Tritium Isotopes

Tritium (3H) and carbon (13CDIC and 14CDIC) isotopic 

data can be used to infer groundwater residence time (age), 

or the length of time between recharge and collection of a 

groundwater sample. Large amounts of tritium and 14C were 

injected into the atmosphere during or after the period of 

above-ground testing of thermonuclear weapons from 1953 to 

1963. 

Tritium is a radioactive isotope of hydrogen that has 

a half-life of about 12.3 years. It is present at elevated 

concentrations in groundwater that was recharged during 

or after the weapons-testing period. Groundwater with 

tritium concentrations greater than 0.5 tritium units (TU) are 

categorized as modern, and waters with concentrations less 

than 0.5 TU are categorized as pre-modern (recharged prior to 

1952).

Carbon-14 is a radioactive isotope of carbon that is 

continually produced within the upper atmosphere by natural 

processes. It is incorporated into groundwater as dissolved 

inorganic carbon (DIC) when recharge water is in contact 

with the atmospheric gases. This process occurs mostly in 

the unsaturated zone where gaseous concentrations of carbon 

dioxide (CO2) are substantially increased by microbial activity 

and root respiration. The half-life of 14C is 5,730 years, 

and can be used to estimate groundwater ages as much as 

30,000–35,000 years. Measurements of 14C are compared 

to the concentration present in 1950 (before widespread 

thermonuclear weapons testing increased atmospheric 

concentrations of 14CO2), which is referred to as 100 percent 

modern carbon (PMC). For example, groundwater with a 14C 

concentration of inorganic carbon of 50 PMC is interpreted to 

have an estimated groundwater residence age of 5,730 years 
34 Hydrogeologic Framework of the Yakima River Basin Aquifer System, Washington

Figure 13. Spatial distribution of dissolved methane concentrations and carbon-13 ratios of dissolved methane in groundwater, Yakima River basin 

aquifer system, Washington.

wa19-0148_YakimaGW_Fig.13-surficial hydro units.fault fold T. 15N. T. 13N. T. 11N.

T.09N.T.07N.

R.28E. R.26E. R.24E. R.22E. R.20E. R.18E. R.16E.

Rattlesnake Hills Gasfield

120°30' 120° 119°30'

46°50'46°30'

46°

Parker

Wapato

Umtanum

Moxee

Toppenish

City

Union Gap

Selah

Yakima

Naches

Sunnyside

Kiona

Richland

Prosser

Grandview

Mabton

Satus

Zillah

Granger

Roza

Tieton

Cleman Mtn. Ant ci l ni e

Wahluke Syncline

Cold Creek Syncline

Wapato Syncl ni e

Ahtanum

Moxee

KITTITAS COUNTY

YAKIMA COUNTY

COUNTY

BENTON COUNTY

COUNTY KLICKITAT

YAKIMA

Toppenish Ridge

Wenas Syncline

Umtanum

Anticline

Syncline

Rattlesnake

Hills Structure

Horse Heaven Hil sl Struc ut re

Hog Ranch Structure

Yakim

a Ridge

Ahtanum R di ge

Ahtanum Ridge

A

hta

n

u

m

Creek

Wenas Creek

North

Fork

Dry

Creek

Creek

Toppenish

R VI ER

YAKIMA

aS ut s

Creek

Cowichee Creek

River

Naches

RIVER

YAKIMA

0 5 15 10

10

20 MILES

0 5 15 20 KILOMETERS

M: 0.88

I: -32.7

09N/23E-22J01

EXPLANATION

Surficial hydrogeologic units

Well and local No. sampled for water qualityConcentration of dissolved methane gas, in milligrams per literδ

No data available

13C isotope ratio of

 methane, in per mil

FoldFault

Alluvial unitsUnconsolidated unitsQuaternary volcanicsConsolidated unitsSaddle Mountains unitWanapum unitGrande Ronde unit

: --

M: 0

I: -- M: 16 I: --

M: 0

I: -53

M: 8.7

I: --

M: 0.1

I: --

M: 2.1

I: --

M: 16.5

I: --

M: 25.7

I: --

M: 0.04

I: --

M: 8.17

I: -52.3

M: 4.49

I: -9.87

M: 49.8

I: -35.1 M: 42.7 I: -35.5 M: 0.88 I: -32.7

M: 2.38

I: -45.4

M: 38.25

I: -35.6

M: 10.31

I: -43.1

13N/20E-28Q02

13N/20E-33N01 12N/20E-12K01

10N/17E-27Q01

11N/18E-26M03

10N/20E-04L01

10N/20E-09A01

10N/20E-09A02

11N/22E-30C01

11N/22E-33M01

10N/22E-25F03

09N/23E-22J01 09N/23E-22L01 09N/27E-24N01

08N/28E-09F01

13N/27E-26H01

10N/16E-21D01
Hydrochemistry 35

if there were no indications of any geochemical reactions 

altering the isotopic concentration of DIC. However, within 

deep anaerobic aquifers, such as the more buried CRBG units, 

there can be many factors that influence the concentration of 

DIC, and thus affect the concentration of 14C, which in turn 

will substantially influence estimates of groundwater age. The 

δ13CDIC concentrations are useful in interpreting geochemical 

alterations of 14CDIC and the hydrochemical history of 

groundwater, facilitating better estimates of groundwater 

age. Some samples that contain mixtures of old and young 

groundwater can be identified if both the concentration of 

tritium is greater than 0.5 TU and the 14CDIC concentration 

is substantially less than 100 PMC or less than the values 

measured in recently recharged (young) groundwater. 

Figure 14. Relation between (A) tritium and δ13C and carbon-14 (14C) concentrations in dissolved 

inorganic carbon of groundwater samples from the Toppenish and Yakima basins, Washington 

and (B) δ13C and fluoride and chloride concentrations.

Large variations in 14C and tritium concentrations 

are apparent (fig. 14A and appendix B). The large range in 

δ13CDIC (-17 to 2.8 ‰) is indicative of extensive interaction 

of dissolved carbon in the groundwater system and, 

hence, significantly complicates the application of 14CDIC

concentrations in estimating groundwater residence time. The 

δ13CDIC values are more positive (enriched) in groundwater 

with larger concentrations of chloride and fluoride (fig. 14B, 

appendix B), demonstrating the relation between geochemical 

processes that accumulate conservative solutes as groundwater 

evolves along a flow path. The effect of these processes 

typically is to dilute the 14CDIC concentration, resulting in 

larger apparent groundwater ages. 

08N/24E-01J01

09N/23E-22J01

10N/20E-09A01

10N/16E-21D1

10N/16E-19H01D1

08N/28E-09FO1

09N/27E-24N01

10N/20E-04K

0

20

40

60

80

100

120

-20 -15 -10 -5 0 5

δ13C, IN PER MIL

14C, IN PERCENT MODERN CARBON

Tritium greater than 0.5

Tritium less than 0.5

Tritium greater than 2

δ13C values minimally changed from

 those in recharge areas

A.
36 Hydrogeologic Framework of the Yakima River Basin Aquifer System, Washington

wa19-0148_Figure 14b Flouride-Chloride

δ13C (PER MIL)

0.1

1

10

100

0 10

CONCENTRATION, IN MILLIGRAMS PER LITER

Fluoride

Chloride

-20 -10

δ13C, IN PER MIL

Figure 14.—Continued.

Based on tritium concentrations greater than 0.5 TU, 

the δ13CDIC and 14CDIC of recently recharged groundwater 

generally plot as a cluster (fig. 14A), with 14CDIC values 

typically being larger than 80 PMC and most δ13CDIC values 

ranging from -17 to -13 ‰. These groundwater samples 

are from wells that are relatively shallow (depths ranging 

from 150 to 300 ft) and are typically located in upgradient 

areas with respect to groundwater flow. Samples with the 

lower δ13CDIC values (about -16.9 ‰) were from two wells 

(10N/16E-19H01D1 and 10N/16E-21D1) that were sampled 

to provide information on the composition of relatively 

recent groundwater from the upgradient areas in the western 

uplands of the Toppenish basin near Ft. Simcoe. There was 

a substantial tritium concentration in the 158-ft deep well 

tapping the consolidated unit (21D1); however, the tritium 

concentration in the 425-ft deep well (19H01D1) tapping the 

underlying basalt unit was less than 0.5 TU.

The δ13CDIC and 14CDIC values vary in a generally 

consistent manner (fig. 14A) suggesting some basic patterns 

of change. Waters with higher 14CDIC values that also have a 

high tritium concentration likely include 14C from weapons 

testing, demonstrating that the 14CDIC concentration in recently 

recharged groundwater unaffected by bomb-generated carbon 

is likely in the range of 80 to 85 PMC. Samples from greater 

depths below land surface and at downgradient locations 

typically had more enriched δ13CDIC values and diminished 

14CDIC values—indicating that groundwater has undergone 

substantive geochemical alteration and in some instances has 

been within the groundwater system for many thousands of 

years. Samples from the deepest wells typically displayed the 

greatest differences in values compared to samples collected 

from wells near recharge areas. 

The influence of geochemical reaction on δ13CDIC

values is well demonstrated by the plot of δ13CDIC against 

the concentrations of chloride and fluoride (fig. 14B); 

both chloride and fluoride accumulate along flow paths 

in the CRBG (Steinkampf and Hearn, 1996). As fluoride 

accumulates in groundwater, there is a consistent increase in 

δ13CDIC. The mechanism for the δ13CDIC increase is not well 

known. Microbial production of methane (methanogenesis) 

would result in a similar increase of δ13CDIC, but the δ13C of 

dissolved methane measured in groundwater samples typically 

indicates a non-biogenic source of methane. The mixed 

source of methane, combined with evidence of gas stripping, 

preclude accurate estimation of the extent of the effect that 

methanogenesis would have on the 14CDIC and thus, estimates 

of groundwater age. Alternatively, dissolution of calcite with 

higher 13CDIC values could result in an overall increase in 

13CDIC of groundwater.
Hydrochemistry 37

Groundwater represented by the data plotted in the 

shaded area on the left of figure 14A show minimally changed 

δ13CDIC values from those in the recharge area having 

a concurrent decrease in 14CDIC from about 80 PMC to 

somewhere in the range of about 10 to 20 PMC. If the change 

in 14CDIC is due to solely radioactive decay, it would represent 

about 2 to 3 half-lifes, which is equivalent to 11,500–

17,000 years. Assuming groundwater flow path lengths from 

recharge area to sampled well locations are on the order of 15 

to 30 mi, groundwater flow velocities would be in the range of 

0.01 to 0.04 ft/d. These estimates would include a component 

of vertical flow because some of the sampled wells were in 

upward flow areas. Previous estimates of groundwater flow 

velocities in the deeper basalt units on the basis of numerical 

simulation were on the order of 0.1 to 0.2 ft/d (Vaccaro, 1999) 

and 0.001 ft/d on the basis of 14CDIC concentrations (Reidel 

and others, 2002). 

HELIUM NEON ARGON KRYPTON XENON

10-9

10-8

10-7

10-6

10-5

10-4

10-3

Groundwater

Air saturated water

 at 10°C

CONCENTRATION OF GAS AT STANDARD TEMPERATURE AND PRESSURE,

IN CUBIC CENTIMETERS PER GRAM OF WATER

Air saturated water

 at 20°C

Figure 15. Concentrations of noble gases in groundwater samples from Yakima River basin 

aquifer system, Washington, and calculated concentrations of noble gases in air-saturated water.

Noble Gases

Helium and other noble gases (neon, argon, krypton, 

and xenon) are present in groundwater within the aquifer 

system, and their concentrations can provide information on 

the source or sources of the gases. Additionally, the isotopic 

concentrations of helium also provide information on its 

source or sources. To estimate if the source for any of the 

gases was upward vertical migration from the Earth’s mantle, 

water samples from nine wells were analyzed by isotopic 

mass-spectrometry (Stute and Schlosser, 2000).

Concentrations of helium, neon, argon, krypton, and 

xenon in groundwater in the samples are shown in figure 15

along with the calculated equilibrium air-saturation values 

for recharge occurring at 10 and 20°C (Mazor, 1991). With 

the exception of helium, the concentrations of the gases are 
38 Hydrogeologic Framework of the Yakima River Basin Aquifer System, Washington

within the expected solubility range for dilute natural waters 

saturated with atmospheric gases during the recharge process 

in the unsaturated zone. These measurements indicate that the 

atmosphere is the primary source of these noble gases detected 

in the groundwater of the basin. 

Concentrations of helium (He), and to a lesser degree, 

neon, exceed air-saturated concentrations levels. Other than 

‘excess air,’ which are air bubbles that can become trapped 

at the water table by rapidly changing water levels and create 

over-saturated concentrations (Heaton and Vogel, 1981), 

other sources of neon in groundwater are not expected to be 

significant. Additional sources of helium commonly found 

in groundwater include that produced by radioactive decay 

and externally produced helium transported into the aquifer. 

Sources of helium can be partially distinguished on the basis 

of the 3He/4He ratio in the sample normalized to the 3He/4He 

ratio in air as R/Ra = (3He/4He)sample / (3He/4He)air. Helium 

produced from radioactive decay of tritium (tritigenic helium, 

3He) has a R/Ra greater than 1, radiogenic helium generated 

from the decay of naturally occurring uranium and thorium in 

the rock matrix has a R/Ra less than 1, and helium transported 

from deeper mantle sources has a R/Ra greater than 1 (Lupton, 

1983; Solomon, 2000). For water with a R/Ra greater than 

1, one cannot distinguish the source of helium without other 

types of data. For R/Ra less than 1, one cannot explicitly 

determine if part of the helium is from a mantle source, only 

that the predominant source is radiogenic helium. But mantle 

helium is so enriched with 3He that the likely source is mantle 

derived.

The normalized helium ratio in the samples ranged 

from 0.01 to 0.43, indicating that the predominant source 

of excess (above atmospheric concentrations) helium in the 

groundwater samples was radiogenic decay of uranium and 

thorium. Measureable increases in helium concentrations due 

to radiogenic production require on the order of thousands 

of years to accumulate (Solomon, 2000). Reidel and others 

(2002) suggest a helium accumulation rate for pore water 

in the CRBG of 1.7 × 10-11 cubic centimeter of helium (at 

standard temperature and pressure) per year per gram of 

water (cc He (STP)/yr per gram of water). After accounting 

for atmospheric concentrations and assuming the above 

accumulation rate, the helium data indicate that excess helium 

concentrations greater than 1 × 10-7 cc He (STP)/g water 

would be needed to yield estimates of groundwater ages on 

the order of thousands of years and more. It is of interest that 

the three groundwater samples containing less than 10-7 cc He 

(STP)/g water and having estimated ages in hundreds of years 

also contained tritium at concentrations 5–38 TU, which is 

indicative of modern groundwater. As with the carbon isotope 

data, this further shows the need for using multiple methods 

to improve our understanding of groundwater ages and the 

vertical connections in the flow system. 

Groundwater in the Yakima River Basin

Water derived from rainfall and snowmelt recharges the 

aquifer system in the Yakima River basin and moves through 

the system from upland areas to the lowlands. Recharge 

derived from irrigation in the lowlands moves to farm drains 

and streams in the structural basins. The movement of the 

water is influenced by topography, geologic structure, and 

hydraulic characteristics of the sediments and rocks. This 

groundwater is present under unconfined (water table) to 

confined conditions. Changes in recharge and discharge 

conditions, and the withdrawal of groundwater for multiple 

uses affects water levels, streamflow, and water availability for 

both short and long periods.

Occurrence

Groundwater occurring in the hydrogeologic units of the 

aquifer system originated as recharge that was derived from 

rainfall, snowmelt, and, starting in the 1880s, irrigation. As 

part of this study, Vaccaro and Olsen (2007a) estimated daily 

recharge to the Yakima River basin aquifer system using the 

USGS Precipitation-Runoff Modeling System (Leavesley 

and others, 1983) and the Deep Percolation Model (Vaccaro, 

2007) that are contained in the USGS Modular Modeling 

System (Leavesley and others, 1996). Recharge was defined 

as water leaving the active root zone or, for barren soils, 

the bottom of the mapped soil column, and is considered a 

‘potential’ amount of recharge because a large part of the 

estimated recharge in the uplands does not enter the regional 

groundwater flow system but is discharged locally along short 

flow paths to streams. Recharge was estimated for water years 

1950–2003 on the basis of a coverage of composite historical 

land use and land cover (herein called current conditions); 

recharge was also estimated assuming that there had been no 

human activities during that period (assumed predevelopment 

conditions). In addition, the monthly values of currentcondition recharge that were aggregated from the estimated 

daily values by Vaccaro and Olsen (2007a) were refined and 

made available by Vaccaro and Olsen (2007b) in a spatially 

consistent and accessible format for water years 1960–2001—

the period of interest in constructing a groundwater flow 

model. The monthly values were locally refined to account 

for decreased surface-water deliveries and application rates 

during the prorating years in the major irrigation districts with 

proratable rights (Vaccaro and Olsen, 2007b).

Potential mean annual recharge for current conditions 

for water years 1950–2003 was estimated to be 15.6 in. 

or 7,149 ft3/s (about 5.2 million acre-ft), which is about 

58 percent of the mean annual precipitation (Vaccaro and 

Olsen, 2007a). When predevelopment conditions were 

assumed, estimated recharge was 11.9 in. or 5,450 ft3/s 

(about 3.9 million acre-ft) (Vaccaro and Olsen, 2007a). 
Groundwater in the Yakima River Basin 39

Predevelopment recharge was about 97 percent of the 

estimated mean annual unregulated streamflow, indicating 

that only about 3 percent of the unregulated streamflow was 

supported by surface runoff, which is consistent with the 

results of Mastin and Vaccaro (2002).

Estimates of recharge were extended beyond the eastern 

boundaries of the Yakima River basin to the Columbia River 

to include an additional 808 mi2. This area includes 700 mi2

of the extended study area and another 108 mi2 within the 

basin that was not included in the area analyzed by Vaccaro 

and Olsen (2007a); thus, the total recharge-estimation area 

is coincident to the extended study area. The methods used 

to estimate recharge for this 808 mi2 area is described in 

appendix C. In this area, the mean annual recharge for current 

conditions for water years 1960–2001 was estimated to be 

about 1.55 in. or only 92 ft3/s. This relatively small amount 

of recharge is due to the general lack of human activities 

(especially surface-water irrigation) and the low mean annual 

precipitation in this area. The mean annual precipitation for 

the 1971–2000 climate normal (Spatial Climate Analysis 

Service, 2006) in this area ranged from about 6 to 31 in., with 

more than 59 percent of the area receiving less than 10 in. The 

greater precipitation quantities mainly occur in the uplands 

in the northern-most part of this area near Park and Caribou 

Creeks.

The spatial distribution of current-condition mean annual 

recharge for water years 1960–2001 for the extended study 

area (fig. 16) shows the large spatial variability of recharge. 

Within the area of the Yakima River basin analyzed by 

Vaccaro and Olsen (2007a), mean annual recharge for this 

base period was about 15.2 in. or 6,820 ft3/s (about 4.9 million 

acre-ft). These values account for the refinements in selected 

irrigation districts for the years with prorating and for the 

different base period (1960–2001 in contrast to 1950–2003). 

For the complete extended study area, mean annual recharge 

was estimated to be about 13.6 in. or 6,950 ft3/s. Note that 

because much of the recharging water discharges locally, it is 

not available for use but supports streamflow.

The large quantity of recharge in the low-lying structural 

basins, where mean annual precipitation ranges from about 

6 to 9 in., is due to the application of surface water to 

croplands and canal/lateral leakage. These factors account 

for the estimated 1,699 ft3/s increase in recharge from 

predevelopment to current conditions within the area modeled 

(6,100 mi2); the increase in recharge from predevelopment to 

current conditions for the 808 mi2 area (described above) was 

only about 8 ft3/s. The distribution of these large quantities 

of recharge is consistent with the location of the surfacewater irrigation districts (fig. 17). The isotopic composition 

of surface water and shallow groundwater also confirms that 

irrigation is the source of increased recharge. In contrast, the 

large quantity of potential recharge in the uplands (where 

mean annual precipitation typically is greater than about 

30–35 in.) is derived from rainfall and snowmelt. Small mean 

annual recharge quantities, generally less than 2 in. (fig. 16), 

occur where mean annual precipitation is low and there is no 

irrigation (primarily in the areas east of the structural basins). 

Mean annual recharge for current conditions was estimated to 

be less than 2 in. over about 37 percent of the extended study 

area (about 2,553 mi2), and within this area recharge averaged 

about 0.45 in. or 86 ft3/s (62,300 acre-ft).

The amount of the estimated potential recharge that 

actually enters the aquifer system is a function of the hydraulic 

characteristics of the surficial hydrogeologic units, the depth to 

the water table, and land-surface slope. For example, coarsegrained surficial units such as the alluvial units (table 1 and 

fig. 8) can readily accept recharge. In contrast, most of the 

recharge in the bedrock-floored, humid, forested-upland slopes 

of the Cascade geologic province (where the bedrock units 

occur) discharges as shallow subsurface groundwater flow to 

upland streams (Mastin and Vaccaro, 2002), and thus is not 

available to recharge the deeper parts of the aquifer system. 

Recharge in some of these upland areas, especially in Kittitas 

County, is limited because the bedrock generally has a much 

lower hydraulic conductivity and infiltration capacity than the 

overlying soils and (or) unconsolidated deposits, which also 

are generally thin or missing (Jones and others, 2006; fig. 8). 

On a long-term basis, only about 34 percent of the potential 

mean annual recharge (percentage varies on an interannual 

basis) was estimated to have entered the regional groundwater 

flow system in the bedrock units in the upper Yakima River 

basin in Kittitas County (Vaccaro and Olsen, 2007a; Mastin 

and Vaccaro, 2002, fig. 6). In addition, the steep slopes in 

these areas, combined with the conductivity contrast between 

the soils (and any developed porous regolith) and the bedrock, 

result in a relatively large lateral component of flow that 

limits vertical movement (Polubarinova-Kochina, 1962)—the 

steeper slopes increase the probability of potential recharge 

moving laterally to discharge as shallow subsurface flow. In 

contrast, the surficial CRBG units generally can accept most 

of the potential recharge (Davies-Smith and others, 1988; 

Bauer and Vaccaro, 1990; Hansen and others, 1994). In the 

dissected outcrop areas of the CRBG, however, the potential 

recharge to deeper parts of the units would be limited due to 

local discharge from the shallow groundwater flow system to 

streams and “cuts” along canyon walls. This recharge supports 

local streamflow and evapotranspiration. In some areas, the 

water table may be near the land surface during some periods 

of the year, and thus part of the recharge may be rejected and 

would be expressed as shallow subsurface groundwater flow 

and (or) overland flow (surface runoff).

The recharge that reaches the water table may have 

traveled for less than a day from below the root zone in 

areas with shallow water tables to as long as tens or even 

hundreds of years where the water table is deep. In the case 

of a shallow water table, the pulses of recharge are reflected 

by seasonal to event variations in groundwater levels. In 

areas with a deep water table, such pulses are attenuated with 

depth and approach a constant rate that is best approximated 

by an estimate of long-term mean annual recharge. In these 

latter areas, variations in water levels typically are caused by 

pumpage and (or) vertical leakage.
40 Hydrogeologic Framework of the Yakima River Basin Aquifer System, Washington

0 5 10 20 30 MILES

0 5 10 20 30 KILOMETERS

Cle Elum

Parker

Wapato

Ellensburg

Umtanum

Kittitas

Thrall

Toppenish

Moxee City Union Gap

Yakima

Selah

Naches

Sunnyside Richland

Kiona

Kennewick Prosser

Grandview

Mabton

Satus

Zillah

Granger

Roza

Easton

Teanaway

Tieton Rimrock

121°

47°

47°

30'

46°

121°30' 120°30' 120° 119°30'

46°

30'

EXPLANATION

Less than 0.5

25 to 48

Greater than 48

Mean annual recharge, in inches 

13 to 24

7 to 12

0.6 to 2

3 to 6

wa19_0148_fig16-Mean Annual Recharge

T.

24

N.

T.

22

N.

T.

20

N.

T.

18

N.

T.

16

N.

T.

14

N.

T.

12

N.

T.

10

N.

T.

8

N.

T.

6

N.

R.10E. R.12E. R.14E. R.16E. R.18E. R.20E. R.22E. R.24E. R.26E. R.28E.

Figure 16. Spatial distribution of mean annual recharge for current conditions, 1960–2001, Yakima River basin aquifer 

system, Washington.
Groundwater in the Yakima River Basin 41

wa19-0148_fig17-IrrigationDistricts

Kennewick Irrigation District

Irrigation districts in the Yakima River Basin

Kittitas Reclamation District

Roza Irrigation District

Sunnyside Valley Irrigation District

Yakima-Tieton Irrigation District

Wapato Irrigation Project

All other irrigation districts

KITTITAS COUNTY

YAKIMA COUNTY

COUNTY

BENTON COUNTY

KLICKITAT

COUNTY

YAKIMA

Bumping

Lake

Cle Elum River

Bumping River

Ahtanum Creek

Tieton River

Wenas Creek

North Fork

Dry Creek

RIVER

YAKIMA

Satus

Creek

Cle

Elum

Lake

Rimrock

Lake

Kachess Lake

Keechelus Lake

Lake

Wallula

Teanaway River

Umtanum Creek

Little Naches River

Cowiche Creek

North Fork

River

Naches

RIVER

YAKIMA

RIVER

YAKIMA

Cle Elum

Parker

Wapato

Ellensburg

Umtanum

Kittitas

Thrall

Toppenish

Moxee City Union Gap

Yakima

Selah

Naches

Sunnyside Richland

Kiona

Kennewick

Prosser

Grandview

Mabton

Satus

Zillah

Granger

Roza

Easton

Teanaway

Tieton Rimrock

Snoqualmie

Pass

Van Epps

Pass

Esmeralda

Peaks

K I T T I T A S

V A L L E Y

M A N A S T A S H

KACHESS RIDGE

R I D G E

UNION GAP

CLEMAN

MOUNTAIN

TEANAWAY

NORTH RIDGE

U M T A N U M

R I D G E

Deception

Pass

Y A K I M A

 V A L L E Y

AHTANUM RIDGE

COWICHE MTN

AMERICAN RIDGE

CLE ELUM

RIDGE

RIDGE

TOPPENISH RIDGE

R A T T L E S N A K E H I L L S

Y A K I M A R I D G E

H O R S E

H E A V E N

H I L L S

C

A

S C A

D E R

A

N

G

E

W E N AT C H E E

M O U N TA I N S

Gilbert

Peak

121°

47°

47°

30'

46°

121°30' 120°30' 120° 119°30'

46°

30'

0 5 10 20 30 40 MILES

0 5 10 20 30 40 KILOMETERS

EXPLANATION

T.

24

N.

T.

22

N.

T.

20

N.

T.

18

N.

T.

16

N.

T.

14

N.

T.

12

N.

T.

10

N.

T.

8

N.

T.

6

N.

R.10E. R.12E. R.14E. R.16E. R.18E. R.20E. R.22E. R.24E. R.26E. R.28E.

Figure 17. Surface-water irrigation districts, Yakima River basin, Washington.
42 Hydrogeologic Framework of the Yakima River Basin Aquifer System, Washington

Within the Yakima River basin, the percentage 

(rounded) of recharge that occurs in the outcrop areas of the 

hydrogeologic units is about 0.29 percent for the basin-fill 

units, 0.007 percent for the Saddle Mountains, 0.008 percent 

for the Wanapum, 0.13 percent for the Grande Ronde, and 

0.57 percent for the bedrock units. After recharge enters the 

aquifer system, groundwater flows along local to regional 

flow paths. Local flow paths are on the order of feet to a few 

miles, and regional flow paths generally are on the order of 

5–50 mi. Isotope analysis of groundwater samples (described 

in the previous section; see also Hearn and others, 1985; 

Hendry and others, 1992; Wagner and Lane, 1994; Steinkampf 

and Hearn, 1996; Reidel and others, 2002; Gazis and others, 

2007) indicates that groundwater in the surficial units is of 

recent age; groundwater becomes progressively older with 

depth, and in parts of the more deeply buried units in the 

basin, groundwater is as much as and in some cases, more 

than, 10,000 years old. These variations in groundwater 

age highlight the differences between the local and regional 

components of groundwater flow.

Groundwater occurring in the different hydrogeologic 

units moves along various flow paths at rates that depend on 

the hydraulic characteristics of the units and the hydraulic 

gradients. Hydraulic characteristics and hydraulic gradients 

are highly correlated because gradients tend to be steeper in 

poorly transmissive units and flatter in more transmissive 

units. Water moves readily in the unconsolidated units because 

of the large interconnected pore spaces (interstices) in the 

silty sands to gravels and cobbles. Conversely, the rate of 

movement is slow through the small and less interconnected 

pore spaces in the clays present in the units. The semiconsolidated to consolidated sandstone of the consolidated 

units commonly has well-connected but small pore spaces, 

but compressional forces and (or) heat from historical 

volcanism can reduce the pore spaces in sandstone. The shale, 

mudstone, siltstone, and claystone in these units have limited 

interconnected pore spaces, which impedes and slows the 

movement of water. The unconsolidated to conglomerate 

lenses/layers within the consolidated units can have wellconnected pore spaces. Wells completed in the consolidated 

units generally derive their water from sandstone and (or) 

layers and lenses of unconsolidated and conglomerate 

deposits, where most of the groundwater in these units occurs 

and moves.

In the CRBG units, water occurs in fractures, 

interconnected vesicles, and basalt flow-top breccia, scoria, 

and clinker. Most of the water in these units moves through 

the vesicles, rubble, and other interflow material, so that the 

direction of groundwater flow is predominantly parallel to 

the structural gradient/dip of the basalt. The occurrence and 

movement of groundwater between basalt interflow zones is 

along crevices and fractures in the entablature and colonnade. 

Water movement in this part of a basalt flow is predominantly 

vertical but may be reasonably connected laterally in areas 

with an established colonnade. Although individual flows 

of the CRBG can range in thickness from a few inches to 

more than 300 ft, the interflow zones (where most of the 

groundwater occurs and moves) constitute, on average, only 

about 5 to 10 percent of the thickness of an individual basalt 

flow (Swanson and others, 1979a), which limits the occurrence 

and movement of groundwater in the basalts. That is, large 

quantities of groundwater can move through parts of the 

CRBG units (large Kh values), but their overall ability to store 

water is small (small storage coefficient).

In the bedrock units, groundwater occurs in and moves 

through fracture systems in the Paleozoic metamorphic rocks 

(gneiss, schist, phyllite, and amphibolite) present in the 

Manastash and Taneum Creek drainages and the Mesozoic 

ultramafic rocks in the upper Cle Elum and Teanaway River 

drainages. In other bedrock units, groundwater occurs in 

and moves through interconnected interstices in shales and 

sandstones, and through fractures and vesicles in basalt 

and andesite. Except for the Quaternary unit, the bedrock 

units generally are not as conductive as the CRBG units or 

parts of the consolidated units (table 4). However, joints 

within the crystalline rocks are locally numerous enough to 

provide sufficient permeability to support some groundwater 

withdrawals, and groundwater in the interstices in the 

sandstone layers generally can also support withdrawals. 

In some areas, the Tertiary sedimentary unit is composed 

predominantly of clay and shale and the availability of 

groundwater is limited. However, usable quantities of water 

can be obtained from some layers that are recharged in an 

outcrop area and (or) by older water entering the layers by 

vertical flow through overlying or underlying units. The 

Quaternary bedrock unit, which generally is near the crest 

of the Cascade Range, probably is permeable on the basis 

of information for similar rock types of similar ages; for 

example, the Quaternary basalts of the eastern Snake River 

Plain aquifer system where groundwater occurs in fractures, 

flow tops, and vesicles have been shown to be highly 

permeable (Garabedian, 1986; Lindolm, 1996). Gannett and 

Lite (2004) also show that these young volcanics are highly 

permeable. However, too few wells are completed in this unit 

to provide data to assess its permeability and occurrence.

The amount of groundwater in storage can be roughly 

estimated for the basin-fill, bedrock, and CRBG units based 

on the volume of units and an estimate of their effective 

porosities. The total thickness used in the volume calculation 

for the bedrock and CRBG units was limited to 3,000 ft for 

this analysis. Due to the large variations in lithology of all 

units and the paucity of information on effective porosity, 

single values were used in the calculations. These values were 

selected to derive ‘conservative’ estimates of the volume of 
Groundwater in the Yakima River Basin 43

water in storage in the aquifer system. A value of 0.1 was 

selected as an estimate for the clay, sand, gravel, sandstone, 

and shale in the basin-fill units. For the CRBG units, a 

conservative value of 0.04 was selected. Sublette (1986) 

reported that the effective porosity for different parts of the 

basalt flow ranges from 0.002 to 0.41, with representative 

values between 0.02 and 0.14. The lower representative values 

are for the basalt flow interiors and thus, the selected effective 

porosity value of 0.04 for the CRBG units represents the 

volume of basalt consisting primarily of flow interiors. For 

the older bedrock units, a value of 0.01 was selected for the 

analysis. The large range in lithology, as well as the effects 

of diagenesis, fractures, and overburden pressure likely result 

in spatial variations in the effective porosity values of the 

bedrock-unit ranging from 0.001 to 0.45. On the basis of these 

porosity estimates, the amount of water in storage in the basinfill, CRBG, and bedrock units is 43.5, 277, and 52.6 million 

acre-ft, respectively. Several factors should be noted for these 

estimates. First, they are generalized and should be considered 

order-of-magnitude estimates. Second, they are considered to 

be the same for both predevelopment and current conditions 

due to the small change in storage caused by groundwater 

pumpage.These volumes should not be interpreted as available 

in their entirety to meet water-supply needs; dewatering of 

any aquifer is environmentally and economically undesirable. 

The amount of water that may be available is related to water 

quality and environmental, economic, and legal constraints. 

Indeed, estimated recharge is only about 5 million acre-ft 

(about 2 million acre-ft after accounting for discharge to 

streams in the bedrock uplands), and the recharge supports 

in-stream and out of stream uses. Water in storage is 

important, however, because it is the groundwater that moves 

within and through the aquifer system.

Conditions of Occurrence

Groundwater in the aquifer system occurs under watertable to confined conditions. The water table occurs in the 

surficial hydrogeologic units throughout the study area. 

Groundwater in units below the water table occurs principally 

under semiconfined to confined conditions, but is locally 

unconfined where a perched water table exists. The depth to 

the water table (DTW) was mapped in the structural basin 

and in areas outside the basins where data were sufficient 

(fig. 18). The generalized map shows that the water table is 

shallowest in the topographically smooth (low slope) parts of 

the structural basins and is deeper in other parts of the system 

(fig. 18). However, in arid areas such as the Hanford Site 

(fig. 1), the low recharge quantities results in a large DTW in 

the low slope area. 

The DTW reflects the relation between the quantity of 

recharge, hydraulic characteristics of units, and topographic 

setting. The DTW shown on figure 18 is generalized and does 

not represent any particular year or season but rather identifies 

typical ranges. Locally, DTW is highly variable because of 

topographic variations. In the areas where the DTW is not 

shown, there was a lack of water-level data, and in some areas 

the interval boundaries of 81–200 ft and greater than 200 ft are 

highly generalized due to sparse data. These factors are due 

to the fact that of the more than 10,000 water levels analyzed, 

most were in the structural basins, and secondarily, many of 

the remaining water levels were not representative of the water 

table due to the groundwater conditions of the unit or units in 

which a well was completed.

The water table is within about 0–20 ft of land surface 

in the low slope parts of the structural basins that receive 

recharge from surface-water irrigation and in the alluvial river 

valleys with perennial streams (fig. 18). The proximity of 

the water table to land surface is highly variable throughout 

the remainder of the aquifer system, ranging from a few 

feet to more than 500 ft. The shallow water table in parts 

of the surface-water irrigated areas is due to the increased 

recharge (described previously) that started in the late 1890s. 

For example, in describing the relation between irrigation 

and drainage, Jayne (1907) presents information for nine 

wells in the Sunnyside area dug between 1890–1900 that 

shows that by 1902 there were water-level rises from 14 to 

75 ft (the differences in the magnitude of the rises were due 

to the location of a particular well). Such water-level rises 

throughout the irrigated areas during this period resulted in the 

formation of drainage districts for the purpose of constructing 

drainage ditches, also called drains (Jayne, 1907). The shallow 

water table in the structural basins suggests a readily available 

supply of groundwater, but much of this irrigation-derived 

water in the shallow system discharges to drains and streams 

and is relied on to meet downstream uses (both in-stream 

flows and diversions with entitlements). Areas with high 

water tables (shallow groundwater) also are more susceptible 

to contamination from sources at the land surface (Sumioka, 

1998).

The complexity of DTW is due to not only local 

topographic variations but also to local variations in the 

properties of the hydrogeologic units. For example, in some 

areas there are numerous domestic wells with depths between 

200–400 ft and a DTW on the order of 150 ft. However, there 

also are some interspersed, shallow (less than 50 ft deep) wells 

in which the DTW is about 20 ft. In such areas, the shallow 

wells may be tapping a localized perched aquifer that locally 

overlies a low-conductivity layer. Such perched zones were 

described by Newcomb as early as 1959 (Newcomb, 1959). 

Perched water tables generally indicate a combination of 

limited recharge and an underlying impeding layer. For the 

CRBG units, perched water would be most prevalent in the 

low recharge areas east of the Yakima River. Thus, the mapped 

DTW in some of these areas may be most representative of 

perched water. 
44 Hydrogeologic Framework of the Yakima River Basin Aquifer System, Washington

0 5 10 20 30 MILES

0 5 10 20 30 KILOMETERS

121°

47°

47°

30'

46°

121°30' 120°30' 120° 119°30'

46°

30'

EXPLANATION

Depth to water table, in feet

 below land surface

0 to 20

21 to 80

81 to 200

Insufficient data to map

Greater than 200

Bumping

Lake

S Fk

N Fk

Cle Elum River

Bumping River

Ahtanum Creek

Tieton River Wenas Creek

North Fork

Dry Creek

Creek

Toppenish

RIVER

YAKIMA

Logy Creek

Satus

Creek

Cle

Elum

Lake

Rimrock

Lake

Kachess Lake

Keechelus Lake Teanaway River

Umtanum Creek

Little Naches River

Cowiche Creek

Cowiche Creek

River

Naches

RIVER

YAKIMA

RIVER

YAKIMA KITTITAS COUNTY

YAKIMA COUNTY

COUNTY

BENTON COUNTY

KLICKITAT

COUNTY

YAKIMA

Snoqualmie Pass

Van Epps

Pass

Esmeralda

Peaks

K I T T I T A S

V A L L E Y

M A N A S T A S H

KACHESS RIDGE

R I D G E

UNION GAP

CLEMAN

MOUNTAIN

TEANAWAY

NORTH RIDGE

U M T A N U M

R I D G E

Deception

Pass

Y A K I M A

 V A L L E Y

AHTANUM RIDGE

COWICHE MTN

AMERICAN RIDGE

CLE ELUM

RIDGE

RIDGE

TOPPENISH RIDGE

R A T T L E S N A K E H I L L S

Y A K I M A R I D G E

H O R S E

H E A V E N

H I L L S

C

A

S C A

D E R

A

N

G

E

W E N AT C H E E

M O U N TA I N S

Gilbert

Peak

Cle Elum

Parker

Wapato

Ellensburg

Umtanum

Kittitas

Thrall

Toppenish

Moxee City Union Gap

Yakima

Selah

Naches

Sunnyside

Richland

Kiona

Prosser Kennewick

Grandview

Mabton

Satus

Zillah

Granger

Roza

Easton

Teanaway

Tieton Rimrock

wa19_0148.fig18_depth to water table

T.

24

N.

T.

22

N.

T.

20

N.

T.

18

N.

T.

16

N.

T.

14

N.

T.

12

N.

T.

10

N.

T.

8

N.

T.

6

N.

R.10E. R.12E. R.14E. R.16E. R.18E. R.20E. R.22E. R.24E. R.26E. R.28E.

Figure 18. Generalized depth to water table for parts of the Yakima River basin aquifer system, Washington.
Groundwater in the Yakima River Basin 45

DTW fluctuates on both a seasonal and interannual basis 

due to natural variations in precipitation and (or) human 

activities. For example, a hydrograph (fig. 19A) for well 

10N/19E-05R01 (a 20.5-ft deep well) that is completed in 

Unit 2 of the Toppenish basin shows distinct fluctuations, on 

the order of 10 ft, due to seasonally varying recharge. The 

fluctuations are out of phase with typical expected fluctuations 

due to recharge from precipitation because most of the 

recharge in this area (the Wapato Irrigation Project [WIP], 

fig. 17) is derived from canal/lateral leakage and applied 

irrigation surface water. About 80 percent of the mean annual 

recharge at the location of this well (where mean annual 

precipitation is about 7.5 in.) occurs during the April–October 

period. Annual recharge was estimated to range from 19.7 

to 22.2 in. between 1958 and 1960, nearly three times larger 

than annual precipitation. The water-level fluctuations and 

estimated recharge quantities indicate that the specific yield 

of the unit is about 0.16–0.19, which is consistent with the 

deposits described on the drillers’ log and on logs for nearby 

wells.

Similar water-level fluctuations are observed in most 

other irrigation districts. For example, Drost and others (1997) 

present seasonal hydrographs for wells in the surface-water 

irrigated areas in eastern Benton County that peak from 

August through December and reach their low from March to 

May. The seasonal rises also are attributed to the combined 

effects of canal/lateral leakage and infiltration of irrigation 

water. The median seasonal changes in water levels, which 

were classified on the basis of the dominant influence that 

produced the seasonal trend, for numerous wells ranged 

from 1 to 6 ft with maximum changes greater than 31 ft. The 

largest rises were associated with the wells that were classified 

as being most influenced by leakage from canals/laterals, 

especially unlined canals and wells completed in the Pasco 

gravels. 

From late August through at least the beginning of 

the next irrigation season, the water table in surface-water 

irrigated areas declines due to groundwater discharge to 

streams, tile drains, drains, and wasteways. Typically, the 

drainage continues until the next irrigation season, with the 

lowest water levels generally occurring between mid-March to 

early May (fig. 19A; Drost and others, 1997). The variations in 

timing of the highs and lows are a function of location, local 

crop type, and year (interannual climatic variations). Although 

recharge can occur during the winter, the rate of groundwater 

drainage generally is more than the winter recharge rate. 

Under natural conditions, soil moisture in the irrigated areas 

would be near or at wilting point by about October, but the 

moisture added to the soil column during the irrigation season 

allows for winter recharge in these dry areas. However, in the 

southern structural basins the winter recharge quantities are 

smaller than the irrigation season quantities because winter 

precipitation is generally less than 8 in. In addition, Kh values 

of the surficial deposits in the irrigation districts generally 

are large enough to allow for groundwater drainage to exceed 

recharge during the winter.

Water-level hydrographs for water-table wells in areas 

where recharge is derived from precipitation (rainfall and 

snowmelt) have a shape similar to those affected by irrigation, 

but the highest water levels occur in the winter-summer 

period (January–July, depending on location and year) and 

the lowest in the fall-winter period (September–February, also 

depending on location and year). For example, a hydrograph 

for a 30–ft deep well (10N/16E-24E01) completed in coarsegrained deposits near Toppenish Creek shows distinct seasonal 

fluctuations with highs between January and February and 

lows in October (fig. 19B). The fluctuations are due to 

recharge from precipitation and are smaller than fluctuations 

due to surface-water irrigation. Additional water-level 

fluctuations correspond to runoff variations (stream losses) 

in Toppenish Creek. Water-level hydrographs in the wetter 

upland areas with a large seasonal snowpack generally have 

later seasonal highs, typically between April and June, but 

sometimes in July.

Hydrographs for wells in or near major irrigation 

pumping centers are similar to hydrographs for water-table 

wells in areas where recharge is derived from precipitation, 

such as shown in figure 19B. Hydrographs of irrigation wells 

in these areas show the effects of seasonal pumpage. For 

example, in the hydrograph for a 1,510-ft deep composite 

CRBG unit well (10N/17E-27Q01, fig. 19C) the highest water 

levels are in late March to early April and the lowest in late 

September, which is typical of CRBG wells throughout the 

Columbia Plateau (Hansen and others, 1994; Whiteman and 

others, 1994). The seasonal water-level range in this well is 

about 23 ft, but Drost and others (1997) show that the seasonal 

range in basalt-irrigation wells can be as much as 95 ft. 

Typically, in the areas of major basalt-irrigation pumpage, 

the water levels decline throughout an area encompassing 

the pumping centers during the irrigation season and begin 

to rise after the end of the irrigation season; these seasonal 

fluctuations generally are consistent over large areas. For the 

deeply buried basalt units that do not outcrop, the rises can be 

attributed to vertical leakage from overlying/underlying basalt 

flows or units. In areas experiencing long-term groundwaterlevel declines, the levels do not rise to those observed prior 

to the irrigation season because locally the pumpage is larger 

than vertical leakage, lateral inflow, and (or) recharge.
46 Hydrogeologic Framework of the Yakima River Basin Aquifer System, Washington

Figure 19. Depth-to-water in four wells, Yakima River basin, Washington.

WA_0148-fig19ab_Hydrograph_Short-term

1958 1959 1960 1961

MAY JULY SEPT NOV JAN MAR MAY JULY SEPT NOV JAN MAR MAY JULY SEPT NOV JAN MAR MAY

10N/16E-24E01

2000 2001 2002

JULY SEPT NOV JAN MAR MAY JULY SEPT NOV JAN MAR MAY

16

18

20

22

24

10N/19E-05R01

B.

A.

6

8

10

12

14

16

18

DEPTH TO WATER, IN FEET

DEPTH TO WATER, IN FEET
Groundwater in the Yakima River Basin 47

WA_0148-fig19cd_Hydrograph_Short-term (continued)

310

315

320

325

330

335

340 JULY SEPT NOV JAN MAR MAY JULY SEPT NOV JAN MAR MAY

10N/17E-27Q01

D. 8N/22E-03M01

C.

25

30

35

1999 2000 2001 2002

2000 2001 2002

MAY JULY SEPT NOV JAN MAR MAY JULY SEPT NOV JAN MAR MAY JULY SEPT NOV JAN MAR MAY

DEPTH TO WATER, IN FEET DEPTH TO WATER, IN FEET

Figure 19.—Continued.
48 Hydrogeologic Framework of the Yakima River Basin Aquifer System, Washington

The hydrograph for well 8N/22E-03M01 (fig. 19D), 

which is completed in unconsolidated deposits of Unit 1 of the 

Benton basin near the boundary of WIP, also shows distinct 

seasonal fluctuations due to recharge. This 167-ft deep well 

is adjacent to sloping uplands, and water-table wells located 

in such areas, especially where coarse-grained deposits are 

overlain by fine-grained deposits such as the Touchet Beds 

(table 1), have smaller seasonal fluctuations than wells tapping 

the water table in the flatter, central parts of irrigation districts 

(Hansen and others, 1994). Fluctuations in the central part 

of WIP can be more than 15 ft (Kinnison and Sceva, 1963; 

U.S. Geological Survey, 1975). The hydrograph also shows a 

distinct interannual variation due to the interannual variation 

in recharge. For example, water year 2001 was an extreme 

proratable (about 37 percent) drought year and as a result, 

not only was natural recharge much less than average, but 

the application of surface water to crop lands in WIP (more 

than 50 percent of its surface-water entitlement is proratable) 

also was diminished in comparison to non-proratable years, 

as was the amount of water present in the canals, laterals, 

and drains—resulting in a deeper water table and a smaller 

seasonal fluctuation (fig. 19D). The 3-ft deeper water table, 

combined with the specific yield for this area described 

previously, indicates a decrease in recharge in WIP of at least 

6 in. This decrease represents a relatively large quantity of 

recharge; for example, in the study area mean annual recharge 

was estimated to be less than 6 in. over about 3,175 mi2 and 

less than 2 in. over about 2,553 mi2.

Unconfined conditions are highly variable in the study 

area. For example, water levels in two closely spaced wells 

(530-ft deep 8N/30E-22R03 and 52-ft deep 8N/30E-22R04) 

that are completed in the Saddle Mountains are about the 

same and information from the drillers’ logs and seasonal 

water levels indicate that both function as water-table wells; 

interbeds are minimal in this location. In other areas, however, 

water-level data indicate that confined conditions exist at 

much shallower depths than 530 ft. These types of differences 

are principally due to the presence or absence and the highly 

variable nature of interbeds in the CRBG units, the hydraulic 

characteristics of individual basalt flows, and (or) the spatial 

variations in the lithology of the consolidated units. For the 

latter, spatial variation is explained by basin-fill deposits that 

had a variety of sources and were emplaced under a wide 

range of depositional-climatic regimes, and the basin-fill 

deposits and the CRBG units were subsequently affected by 

erosion and structural deformation. In areas where the CRBG 

units are at or near land surface and the quantity of recharge is 

small, groundwater also can occur under perched conditions.

Variations in unconfined conditions also occur in the 

unconsolidated units in the structural basins. For example, 

wells deeper than 400 ft in parts of the Toppenish basin are 

water-table wells, whereas an 8-ft deep well in the AhtanumMoxee basin taps a confined flowing artesian zone. In some 

areas, wells tap shallow unconfined groundwater in cemented 

gravels that function as an unconfined aquifer, whereas 

nearby wells that penetrate through the cemented gravels tap 

an underlying confined aquifer confined by the cemented 

gravels. In a few areas, these differences may be attributed 

to fine-grained terrace deposits overlying the gravels. These 

types of variations appear to be most prevalent in the Ahtanum 

subbasin (Foxworthy, 1962).

There are many occurrences of flowing artesian zones 

in the aquifer system (fig. 20A). Groundwater in these zones 

occurs under confined conditions, which are prevalent in many 

parts of the aquifer system. Water levels in wells in these 

zones are higher than the land surface, and thus uncapped 

wells tapping these zones will flow. These conditions in the 

basin were described as early as 1901 (Smith, 1901) and were 

later discussed by Waring (1913) for parts of the basin, by 

Molenaar (1961), and by Foxworthy (1962) for the Ahtanum 

subbasin. Artesian conditions generally occur where a waterbearing unit dips beneath a unit of low conductivity, such as 

a clay, shale, or a tight sandstone. For flowing artesian zones 

in confined aquifers, the water-bearing unit crops out (or is 

overlain by thin or conductive deposits) and is recharged in 

an area of higher altitude than the overlying low-conductivity 

unit. The outcrop area is the source of high-pressure head 

for the artesian zone. Discharge from the zones also is 

impeded due to the presence of the fine-grained overlying 

unit. For example, upward vertical discharge from the Saddle 

Mountains and Unit 5 in the Toppenish basin is impeded by 

the overlying fine-grained Unit 4 (table 1). These conditions 

are present particularly in basin-like structures, which are 

represented by synclines in the study area, and such conditions 

exist in many areas of the aquifer system (fig. 20A).

The highly variable character and wide-spread 

distribution of artesian zones is indicated by the location 

and depth of more than 500 flowing wells (fig. 20A). The 

wells represent both historical and existing flowing wells on 

the basis of information from Molenaar (1961), NWIS, and 

review of more than 10,000 well logs. The measured discharge 

for 251 of these wells ranged from 0.125 to 3,900 gal/min 

and averaged 230 gal/min. In some areas, such as the upper 

part of the Moxee subbasins, groundwater pumpage from 

these zones has resulted in the reduction of hydraulic head 

(pressure) and the elimination of flowing artesian conditions. 

As another example, hydrographs for wells 13N/24E-27K02 

and 13N/24E-36D01 show the cessation of flowing conditions 

due to pumpage and well 13N/24E-27K03 (drilled to replace 

27K02) shows a continual decline of hydraulic heads 

(fig. 21A). In addition, unpublished field notes from 1971 for 

a water-level measurement of a CRBG well indicate that four 

CRBG-unit wells (11N/17E-13A, -14Q, -15P, -22D; actual 

wells not identified) stopped flowing after the drilling and 

subsequent pumping of a nearby, deep basalt well used for 

irrigation. As a final example, flow from well 13N/24E-24E01 

decreased from 3,900 gal/min in 1925 to 697 gal/min in 1951, 

and of 136 water levels measured between January, 1979 and 

February, 1983, only one was above land surface—essentially, 

the well no longer flows.
Groundwater in the Yakima River Basin 49

Figure 20. Location and depth of historical and present-day (A) flowing wells, and (B) location of historical and presentday springs, Yakima River basin aquifer system, Washington.

wa19_0I48_fig20a-Flowing wells

KITTITAS COUNTY

YAKIMA COUNTY

COUNTY

BENTON COUNTY

KLICKITAT

COUNTY

YAKIMA

0 5 10 20 30 40 MILES

0 5 10 20 30 40 KILOMETERS

EXPLANATION

Basin-fill deposits

Columbia River Basalt Group

Bedrock

Depth of flowing wells, in feet

No well depth data

6 to 150

151 to 400

401 to 650

651 to 2,425

No well depth data

12 to 150

151 to 400

401 to 650

651 to 4,340

401 to 650

651 to 1,055

80 to 150

151 to 400

A.

WASHINGTON

Extended

study area

T.

24

N.

T.

22

N.

T.

20

N.

T.

18

N.

T.

16

N.

T.

14

N.

T.

12

N.

T.

10

N.

T.

8

N.

T.

6

N.

R.10E. R.12E. R.14E. R.16E. R.18E. R.20E. R.22E. R.24E. R.26E. R.28E.

121°

47°

47°

30'

46°

121°30' 120°30' 120° 119°30'

46°

30'
50 Hydrogeologic Framework of the Yakima River Basin Aquifer System, Washington

wa19_fig20b-Springs

KITTITAS COUNTY

YAKIMA COUNTY

COUNTY

BENTON COUNTY

KLICKITAT

COUNTY

YAKIMA

Bumping 

Lake 

S Fk 

N Fk 

Cle Elum River

Bumping River

Ahtanum Creek 

Tieton River Wenas Creek

North Fork

Dry Creek

Creek

Toppenish

RIVER

YAKIMA

Satus Creek

Cle

Elum

Lake

Rimrock 

Lake 

Kachess Lake 

Keechelus Lake 

Lake 

Wallula 

Teanaway River

Umtanum Creek

Little Naches River

Cowiche Creek

Cowiche Creek

River

Naches

RIVER

YAKIMA

RIVER

YAKIMA

Rattlesnake Springs

Cle Elum

Parker

Wapato

Ellensburg

Umtanum

Kittitas

Thrall

Toppenish

Moxee City

Union Gap

Yakima

Selah

Naches

Sunnyside Richland

Kiona

Kennewick

Prosser

Grandview

Mabton

Satus

Zillah

Granger

Roza

Easton

Teanaway

Tieton Rimrock

Snoqualmie

Pass

Van Epps 

Pass 

Esmeralda

Peaks

K I T T I T A S

V A L L E Y

M A N A S T A S H

KACHESS RIDGE

R I D G E

UNION GAP

CLEMAN 

MOUNTAIN 

TEANAWAY

NORTH RIDGE

U M T A N U M

R I D G E

Deception

Pass

Y A K I M A 

 V A L L E Y 

AHTANUM RIDGE

COWICHE MTN

AMERICAN RIDGE

CLE ELUM

RIDGE

RIDGE

TOPPENISH RIDGE

R A T T L E S N A K E H I L L S

Y A K I M A R I D G E

H O R S E

H E A V E N

H I L L S

C

A

S C A

D E R

A

N

G

E

W E N AT C H E E

M O U N TA I N S

Gilbert

Peak

0 5 10 20 30 40 MILES

0 5 10 20 30 40 KILOMETERS EXPLANATION

Roslyn

Kittitas

Selah

Yakima

Toppenish

Benton

B.

Historical and present-day 

 springs

Basins

WASHINGTON

Extended

study area

Base from U.S. Geological Survey and/or

Washington Division of Geology and Earth Resources

digital data, 1983, 1:100,000

Universal Transverse Mercator projection, Zone 10

Horizontal Datum: North American Datum of 1927 (NAD 27)

121°

47°

47°

30'

46°

121°30' 120°30' 120° 119°30'

46°

30'

T.

24

N.

T.

22

N.

T.

20

N.

T.

18

N.

T.

16

N.

T.

14

N.

T.

12

N.

T.

10

N.

T.

8

N.

T.

6

N.

R.10E. R.12E. R.14E. R.16E. R.18E. R.20E. R.22E. R.24E. R.26E. R.28E.

Figure 20.—Continued.
Groundwater in the Yakima River Basin 51

WA_0148-fig21_Hydrograph_Long-term

-250

-200

-150

-100

-50

0

50

100

150

200

250

300

19201930194019501960197019801990

2000

DEPTH TO WATER, IN FEET

13N/24E-27K03

13N/24E-27K02

13N/24E-36D01

50

0

100

150

200

250

300

350

400

DEPTH TO WATER, IN FEET

12N/21E-16L01

12N/21E-16N02

1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000

A. Wanapum unit

B. Wanapum and Saddle Mountains units

Figure 21. Depth-to-water in (A) wells completed in the Wanapum unit, and (B) wells completed in the Wanapum 

(12N/21E-16L01) and Saddle Mountains (12N21E-16N02) units, Yakima River basin aquifer system, Washington.
52 Hydrogeologic Framework of the Yakima River Basin Aquifer System, Washington

Flowing artesian conditions exist locally in some areas, 

whereas in other areas, such as the Yakima basin (Ahtanum 

and Moxee subbasins), there are large, areally-extensive 

productive artesian zones where groundwater occurs under 

confined conditions. Local flowing artesian zones occur in 

many locations, and these zones can be isolated from nearby 

units. For example in the Grande Ronde, well 19N/18E-10SW 

(quarter sections M, L, N, P) penetrated a flowing zone at 

346 ft but the water level dropped after drilling through this 

zone and the final water level in this 763-ft well was 590 

ft below land surface. In contrast, two nearby wells (-10D 

and -10F) drilled to depths of 520 and 380 ft, respectively, 

did not encounter this zone, and their water levels were 

between 275 and 290 ft below land surface. A 708-ft deep 

well (-10R) also did not encounter the flowing zone and had 

a water level of 592 ft below land surface. These two wells 

may have encountered this flowing zone but the hydraulic 

head may have been reduced by cross connections and a 

downward flow regime. (The water levels in the above 

wells also indicate downward flow in this area.) In the next 

section to the east (19N/18E-11), two wells (-11SW and 

‐11L) tap a flowing artesian zone at depths of 322 and 225 ft, 

respectively, whereas a 310-ft well (-11G) is a water-table 

well. Together, this information suggests that the flowing zone 

is locally isolated from some of the surrounding deposits—

further indicating the complexity of the aquifer system. Such 

complexity may be due to unknown structure that locally 

compartmentalizes the flow system. 

Flowing artesian zones are most prevalent in the 

consolidated hydrogeologic units, the CRBG units, and in 

Unit 3 of the Roslyn basin, which is confined by an extensive 

lacustrine layer (Unit 2; table 2, pl. 1); only about 8 percent 

of identified flowing wells were completed in the bedrock 

units. Fine-grained lenses or layers in or overlying these units 

provide a continuous confining section of low conductivity. In 

addition, Smith (1901) hypothesized that compressional forces 

in some of the tighter structural folds, such as in the Moxee 

subbasin, compacted conductive layers (in this case sandstone) 

to reduce their conductivity, thus providing a continuous layer 

of low conductivity. As a result, the same sandstone layer can 

change from an aquifer to a semi-confining/confining unit 

over a distance of less than 10 mi. There also are occurrences 

of shallow wells tapping flowing zones in the surficial 

unconsolidated hydrogeologic units, as wells as in the bedrock 

units (fig. 20A). 

In the CRBG units, a low-conductivity layer may consist 

of interbedded sediments or a basalt flow interior that is 

‘tighter’ (exhibits low Kh and Kv values) than the underlying 

and (or) overlying flow (such as in the wells in 19N/18E-10, 

11 described above). In some areas, water-level data suggest 

that the uppermost part of the Grande Ronde functions as 

semi-confining to confining layer, and it is not known if 

this is caused by the presence of a saprolite layer on top of 

the flow and (or) by the paucity of fractures. In addition, 

in the Wanapum in township 13N, range 24E, sections 25, 

26, 27, and 36 (see fig. 21A, for examples), the flow top of 

the Priest Rapids member used to be a highly productive 

flowing artesian zone, suggesting that in this area the flow 

top functioned as an aquifer that is contained within lower 

conductivity zones (it is overlain by the Mabton unit that is 

mainly composed of shale in this location). Flowing artesian 

zones in tightly folded synclines within the CRBG in some 

parts of the basin are probably the result of compressional 

forces diminishing the interconnectedness of the basalt 

fracture system in the entablature and colonnade (resulting in 

even lower Kv values), similar to that described for sandstone. 

This is clearly evidenced by the exposed central part of folds 

of the ridges in the Umtanum Ridge, where the basalt is so 

compressed that there is an absence of well-defined interflow 

zones and colonnades.

Geologic structures such as faults can offset productive 

units/layers to create a flow barrier that results in a flowing 

artesian zone. These types of zones occur predominantly in the 

CRBG units. For example, some wells in 13N/24E-sections 

25, 26, 27, and 36 (described above) that are upgradient 

(west) of the Cold Creek fault tapped flowing artesian zones 

in the CRBG, but downgradient of the structure water levels 

are lower. Thus, overlying fine-grained layers and geologic 

structure can combine to create a flowing zone. The effects of 

the Cold Creek fault on groundwater flow near the Hanford 

Site were summarized by Reidel and others (2002). Grande 

Ronde wells that range in depth from 62 to 280 ft in 17N/17Esections 12-15 near Manastash Creek in the Kittitas basin 

tap a flowing zone that is upgradient of a mapped fault, but 

wells downgradient from the fault have lower water levels 

and do not flow. Two flowing basalt wells (15N/17E-12N01, 

Wanapum-Grande Ronde composite unit well, 550 ft deep 

and 15N/17E-11A01, Wanapum, 498 ft deep) that are just 

upgradient of a mapped fault had measured closed-in pressures 

of 167 and 85 lb/in2, respectively. The artesian zone in the 

Wanapum that is tapped by well 11A01 (which was noted in 

the driller’s log for well 12N01) is overlain by sandstone and 

shale. Well 12N01 taps artesian zones in both the Wanapum 

and Grande Ronde, which is overlain by a thick sequence of 

the Vantage interbed (principally sandstone). The presence 

of other such artesian zones is suggested by the location of 

the flowing wells and nearby structure perpendicular to the 

flow direction. However, structure can affect the movement of 

groundwater in the basalts without creating flowing zones. For 

example, along the Willow Creek monocline in north central 

Oregon, the lateral hydraulic gradient increases upgradient 

of the monocline and the vertical gradient changes from 

downward to upward near the monocline; just downgradient of 

the monocline, the gradient decreases and the vertical gradient 

changes to downward (Davies-Smith and others, 1988). 

Water levels downgradient of the monocline indicate that 

groundwater is moving through the monocline—it impedes 

but does not block flow.
Groundwater in the Yakima River Basin 53

Faults can impede lateral flow and can also provide an 

area where vertical movement of water can be enhanced or 

impeded (Newcomb, 1961, 1969). For example, Hammer 

(1934), in describing the origin and low pressure of methane 

in the Rattlesnake Hills gas field, where producing zones 

ranged from about 300 to more than 700 ft below land 

surface, shows that gas pressures increased in wet years due 

to downward migration of recharge (increased overlying 

pressure head) and decreased in dry years due to less vertical 

impedance (with more gas moving to the atmosphere). The 

effects of structure on groundwater flow in the CRBG was 

described early by Newcomb (1961, 1969) and was later 

discussed by Steinkampf and others (1985), Davies-Smith and 

others (1988), Hansen and others (1994), Whiteman and others 

(1994), Packard and others (1996), and Steinkampf and Hearn 

(1996).

Structurally controlled artesian zones also occur in both 

the young unconsolidated units and in the bedrock units. In the 

unconsolidated units, at least 15 shallow wells in 18N/18E-27 

ranging in depth from 48 to 127 ft tap a local flowing zone 

composed of cemented gravels. The existence of nearby watertable wells suggests that there is some type of a localized 

structural control (groundwater flow barrier) in this area; 

such groundwater levels can be used to identify flow barriers 

(Steinkampf and others, 1985; Packard and others, 1996). In 

the bedrock units, the flowing zones likely are associated with 

either faults and (or) lateral and vertical changes in rock types, 

such as shale abutting sandstone.

Springs in the basin (fig. 20B) may be representative of 

flowing artesian zones, in which case they typically are related 

to geologic structure. The locations of 362 springs (fig. 20B) 

were obtained mainly from NWIS; additional spring locations 

were obtained from a file of springs that have water rights 

(B. Johnson, Washington State Department of Ecology, written 

commun., 2007). Most springs emanating from the bedrock 

units are probably fault-controlled, although some may be 

fracture-controlled. In the former case, the faults form lateral 

flow barriers but provide a conduit for vertical movement of 

groundwater. Springs also may be due to the truncation of a 

water-bearing unit, such as a basalt interflow zone in a streamcut valley, or springs may be derived from precipitation 

recharge that discharges in seeps downslope from the recharge 

source (as described by Smith [1901] for many springs on the 

south slope of Rattlesnake Hills). A well upgradient of a spring 

may or may not be a flowing well.

Measured or estimated discharge for 207 of the 362 

springs (fig. 20B) ranged from 0.25 to 2,400 gal/min, and 

averaged 76 gal/min with a median of 8 gal/min. The two 

largest springs are in the basalt units, as are most springs 

flowing at more than about 3–5 gal/min. The largest spring, 

the Clerf Spring (17N/20E-06A01S), discharges from the 

Grande Ronde near folds and a mapped fault (Smith, 1901), 

and had a measured discharge of 2,400 gal/min in 1953. 

Rattlesnake Springs (12N/25E-29B01S) discharge from the 

Saddle Mountains, and had a measured discharge of 585 gal/

min in 1907, when it was used to irrigate 100 acres on the 

Benson ranch (Waring, 1913). Measured flow at these springs 

averaged about 209 gal/min over the period October 1990 to 

May 1993 (Dinicola, 1997), suggesting potential effects of 

upgradient pumpage on reduced spring flow. Spring flows of 

this magnitude discharge from the CRBG units throughout the 

Yakima Fold Belt, for example, in Klickitat County. 

Although semiconfined to confined conditions generally 

exist below the water-table system, there are occurrences 

of perched groundwater zones. For example, in the Red 

Mountain-Badger Mountain area in eastern Benton County 

(the southern extension of the Rattlesnake Hills structure), 

most domestic and irrigation wells in the uplands are deeper 

wells and water levels (mapped by Drost and others, 1997) 

are much lower than land surface. However, there also are 

interspersed shallow wells with much higher water levels. The 

small number of these wells suggests a locally perched water 

table in this area. Similar situations are also noted throughout 

the study area, especially in parts of the Rattlesnake Hills, 

Rattlesnake Mountain, Ahtanum-Moxee basin, Selah basin, 

and in areas outside of the structural basins in Kittitas County, 

particularly to the east. 

Flow System

Groundwater moves through the aquifer system from 

the uplands (high land-surface altitude—topographic highs) 

to surface drainage features in the lowlands, principally to 

the Naches and Yakima Rivers and to the Columbia River 

in the eastern part of the extended study area. Groundwater 

movement is affected by topography, geologic structure, 

natural recharge, discharge locations, hydraulic characteristics, 

recharge from the use of water (principally surface-water 

irrigation), and groundwater pumpage.

In the upper part of the flow system, groundwater levels 

are a subdued replica of the land surface. High-conductivity 

hydrogeologic units have water-table surfaces that are the 

most subdued replica of land surface; conversely, in a finegrained unit (such as the Touchet Beds or low-permeability 

granite), water-table surfaces more closely mimic topographic 

variations. Departures from this general relation between 

water-level patterns and grain size occur where the water 

table is deep, which is related to the quantity of recharge. That 

is, where the quantity of recharge is small, for example less 

than 1 to 2 in/yr, the water table generally is deep and ‘flat,’ 

especially where recharge is less than about 0.5 in/yr.

The effect of recharge on groundwater movement 

decreases with distance from the outcrop or recharge area and 

with depth because movement of groundwater is affected by 

the depth of burial of a unit. Thus, flow in the deeper parts of 

the system (such as in Grande Ronde in the central Toppenish 

basin) is controlled primarily by hydraulic characteristics 
54 Hydrogeologic Framework of the Yakima River Basin Aquifer System, Washington

of the unit itself, the thickness and hydraulic characteristics 

of overlying units, and by regional discharge locations. 

Therefore, vertical leakage between hydrogeologic units is 

an important component of flow in the aquifer system. Flow 

in the deeper parts of the Grande Ronde also is affected by 

the topography of the underlying older Tertiary units. This 

topography, which would be expressed in the thickness of the 

Grande Ronde, is largely unknown, however, because only a 

few wells penetrate the unit.

As a result of the factors described above, the movement 

of groundwater to discharge locations can be on the order of 

hours to days in the shallow system to millennia in the deeper 

system, as is indicated by the large variations in groundwater 

ages estimated from carbon isotopes and concentrations of 

excess helium data.

Typical of groundwater flow systems, most of the 

movement of groundwater occurs in the upper part of the 

Yakima River basin aquifer system and decreases with depth 

within the system. This is due largely to the effect of recharge 

being derived from surface-water delivery and application 

in the lowlands and from precipitation in the humid uplands. 

For example, Hendry and others (1992) show the presence 

of tritiated water beneath WIP in the alluvial aquifer and the 

underlying aquifer unit contained in the Ellensburg Formation 

in the Toppenish basin, whereas water samples from the 

deeper CRBG were nontritiated. In addition, the δD and 

δ18O values of surface water and shallow groundwater are 

similar due to the effects of the large recharge quantities in 

the surface-water irrigated areas but the values are different 

from those in water from deeper wells. Excluding the humid 

uplands, most of the flow or activity in the system occurs in 

the upper 100–300 ft of the system, whereas much less water 

moves in the more deeply buried parts of the system. Flow in 

the upper part of the system dominates the seasonal and annual 

water budget (groundwater flow). Overlain on this active part 

of the flow system is the larger regional flow system. Thus, an 

understanding of the water budget and movement of water in 

this upper part is needed to obtain a reliable water budget for 

the deeper part of the system because the water budget for the 

upper part of the system overwhelms the water budget of the 

deeper part. 

Except for groundwater flow in the deeply-buried 

parts of the system, large-scale structural control 

compartmentalizes the flow system (Kinnison and Sceva, 

1963; Hansen and others, 1994; Bauer and Hansen, 2000). 

The compartmentalization limits the length of the flow paths, 

resulting in relatively short paths for such a large aquifer 

system. Structural control is exerted primarily by the major 

ridges in the basin (figs. 7 and 8) such as, from north to south, 

Naneum Ridge, Ainsley Canyon anticline, Manastash Ridge, 

Umtanum Ridge, Cleman Mountain, Cowiche Mountain, 

Yakima Ridge, Rattlesnake Hills-Mountain, Ahtanum Ridge, 

Toppenish Ridge, Snipes Mountain, and the Horse Heaven 

Hills structure (Kinnison and Sceva, 1963; Newcomb, 1970; 

Hansen and others, 1994; Reidel and others, 2002; Jones and 

others, 2006). In addition, the Naneum Ridge anticline extends 

southward along the eastern boundary of the Yakima River 

basin to the Hog Ranch structure; together, they provide a 

north-south structural control on the flow system extending 

from Rattlesnake Hills to about the northern boundary of 

the basin. Combined, they also are called the Hog Ranch 

uplift (Smith, 1988) and the Hog Ranch-Naneum Ridge 

anticline. This structural control also is exerted locally. For 

example, Kirk and Mackie (1993) show the control of the Bird 

Canyon fault and the Hog Ranch-Naneum Ridge anticline 

on groundwater flow in the Saddle Mountains and Wanapum 

units in the Moxee-Black Rock valley. The structural/geologic 

history of the study area has been most recently summarized 

by Reidel and others (2002). As a result of this structural 

control throughout the system, down-valley groundwater flow 

in the basin-fill deposits in the structural basins generally is 

terminated with minimal underflow at all outlets except for 

the Eastern Benton basin, which does not have a structurally 

controlled outlet. Therefore, changes in recharge and 

discharge in five of the six structural basins principally are 

only promulgated down-valley through changes in streamflow 

leaving a basin.

Down-valley flow also is terminated in the upper parts 

of the bedrock and CRBG units in all but the Eastern Benton 

basin. Topographic and structural control also can lead to the 

termination of groundwater flow paths in the bedrock and 

CRBG units at greater depths. For example, Bauer and others 

(1985) and Hansen and others (1994) show groundwater flow 

paths in the Wanapum in the Yakima and extended Toppenish 

basins being directed towards the basin outlet and to the 

Yakima River, respectively. The control is represented by the 

topographic highs that are the major structural ridges, such 

as Ahtanum Ridge-Rattlesnake Hills and Toppenish Ridge. 

Topographic and structural controls on regional flow systems 

were described as early as 1940 by Hubbert (1940) and later 

by Toth (1963a, 1963b, 1978).

Groundwater in the basin-fill deposits in the 

Roslyn, Kittitas, and Yakima basins that is not lost to 

evapotranspiration from the water table ultimately discharges 

to drains and streams upgradient from the basin outlets; 

only minor amounts of groundwater discharges downvalley as underflow in the alluvial units. For the Selah basin, 

some discharge occurs as underflow along the Naches and 

Yakima River outlets. In the extended Toppenish basin, 

groundwater discharges from the basin-fill deposits by 

evapotranspiration and to drains, tile drains, and streams. Due 

to the lack of basin-fill deposits at the basin’s outlet, most 

of the groundwater in the basin-fill deposits of the extended 

Toppenish basin has been discharged by about Prosser, and 

groundwater underflow is minimal downstream from the 

approximate location in the Yakima River of the Spring 

(Snipes) Creek complex. This complex is a relic drainage that 

functions as a drain that receives both surface water (spill and 

return flow) and groundwater (return flow) from irrigation. 
Groundwater in the Yakima River Basin 55

Groundwater underflow mainly occurs in the thin alluvial 

deposits along the Yakima River near where it exits the basin. 

In the Eastern Benton basin, groundwater that is not lost to 

evapotranspiration discharges to the Yakima and Columbia 

Rivers and to drains and wasteways.

The water-level contours and generalized direction of 

groundwater flow in the surficial hydrogeologic units in the 

structural basins (pl. 3) and in the basalt units (pl. 4) highlight 

some of the above aspects. Actual water levels and flow 

directions are more complex than illustrated due to canal/

lateral leakage, irrigation, drains, streams, pumpage, variations 

in recharge, spatially varying hydraulic characteristics, and 

topographic setting. Together, these factors locally affect the 

shape of the water-level contours and thus, flow directions 

and hydraulic gradients. These factors also affect the DTW, 

which locally is much more complex than illustrated on 

the generalized map (fig. 18). The water-level information 

described previously was used to construct these maps. Note 

that water-level information was most abundant for the upper 

part of the aquifer system and the number of measured water 

levels declined with depth.

The configuration of the water table in the surficial 

deposits in the Roslyn, Kittitas, and Yakima basins clearly 

shows groundwater moving towards the alluvial aquifer with 

streams and ultimately to the basins’ outlets (pl. 3). This is 

especially true in the Kittitas and Yakima basins because of 

their shapes and narrow outlets with thin basin-fill deposits. 

For both the Kittitas and Yakima basins, major drains, such 

as Wilson and Cherry Creeks in the Kittitas basin and Wide 

Hollow Creek and Moxee drain in the Yakima basin, capture 

most of the shallow groundwater originating from surfacewater irrigation. Although the Roslyn basin also has a narrow 

outlet, groundwater movement is toward the rivers and drains, 

rather than toward the basin outlet, throughout most of the 

basin because it is long and relatively narrow. Thus, most of 

the groundwater will have discharged to the Yakima River 

before it reaches the basin’s outlet that abuts the Kittitas basin.

Groundwater flow also is directed to the outlet of 

the Selah basin, but underflow along the Naches River to 

the Toppenish basin is indicated by the contours (pl. 3); 

this underflow also was suggested by Kinnison and Sceva 

(1963). In addition, the contours show that the flow system is 

compartmentalized into three distinct flow systems—Wenas 

Creek in the northeast Selah basin, Naches River in the center, 

and Cowiche Creek (with additional compartmentalization 

between the North and South Forks in the Cowiche Creek 

drainage) due to topographic setting and geologic structure; 

such multi-compartmentalization will be described in more 

detail for the Eastern Benton basin. The contours and flow 

lines for the extended Toppenish basin show that a large part 

of the flow is directed towards the Yakima River by about 

Toppenish Ridge. After Toppenish Ridge, the basin becomes 

narrower and the flow contribution towards the river is similar 

to that in the Roslyn basin. Most of the remaining groundwater 

moves towards the Yakima River by Prosser and, on the basis 

of contributing area, only a small amount of the groundwater 

in the Toppenish basin moves in the surficial deposits between 

Prosser and the Spring (Snipes) Creek complex.

The flow system is more compartmentalized in the 

Eastern Benton basin than in the other basins (pl. 3) due to 

its location, topographic setting, and geologic structure. This 

area is bounded between Townships 8N and 9N and Ranges 

27E and 28E, and includes the Rattlesnake Hills structure 

that is expressed as the uplands containing Red Mountain, 

Candy Mountain, and Badger Mountain. Except where the 

Saddle Mountains outcrops, these uplands are overlain by 

the fine-grained Touchet Beds. Groundwater moves both east 

and west in Badger Coulee from a groundwater divide that 

is east of Badger—westward toward the Yakima River near 

Benton City and eastward toward the Columbia River. Flow 

in the uplands moves towards, (1) Badger Coulee, (2) West 

Richland from the gap between Red and Candy Mountains, 

and (3) the Yakima River on the west. Except for the gap, 

the geologic structure in the uplands generally limits the 

northerly and northeasterly flow to the area north of the Red 

Mountain-Badger Mountain structure. The northerly flow from 

the uplands is bifurcated near West Richland with flow to the 

northeast towards the Columbia River and to the northwest 

to the Yakima River. Although few data are available, the 

southerly flow from the Rattlesnake Hills structure in the 

uplands may be redirected to the northwest by Goose Hills 

(an expression of an anticline and possible flow barrier in 

the southeast) and to the north and northeast by another 

topographic high in 8N/28E-17 that is also an anticline and 

close to a thrust fault. Groundwater also flows toward the 

Yakima River from the west and northwest from Rattlesnake 

Mountain from just north of Kiona/Benton City to about Horn 

Rapids; the river is incised in the Saddle Mountains in part of 

this reach. Drost and others (1997) concluded that the Saddle 

Mountains gains water from the Yakima River in part of this 

reach. Flow from about Horn Rapids to the the mouth of 

Yakima River is toward the Columbia River, and the waterlevel contours indicate that the Yakima River is losing water 

over part of this reach. This latter aspect is consistent with the 

findings of Brown (1979), Lindberg and Bond (1979), and 

Drost and others (1997). 

Groundwater levels in the basalt units (pl. 4) generally 

parallel the land surface or, where a unit is buried, the dip of 

the basalt because most groundwater occurs and moves in 

the interflow zones. Where the units are deeply buried in the 

structural basins, water-level contours are smoother (lower 

hydraulic gradient) than those in the uplands, which are 

typically outcrop areas. The water-level contours mapped for 

the CRBG units are generalized due to sparse data in many 

locations and large variations in water levels with depth; two 

closely-spaced wells that are completed at different depths 

in a unit can have large differences (more than 200 ft) in 

water levels. The maps show the authors’ representation of 

average water levels for a unit based on available data and 

hydrologic judgment. In areas of sparse data for a particular 
56 Hydrogeologic Framework of the Yakima River Basin Aquifer System, Washington

unit, water levels for an overlying unit, previously published 

maps (Bauer and others, 1985; Lane and Whiteman, 1989), 

and model-calculated groundwater levels (Hansen and others, 

1994) were used to help guide the contouring of water levels 

to provide a more complete picture of the flow system. Thus, 

actual groundwater levels may be higher or lower than those 

estimated, especially in the Satus Creek basin and eastern 

Kittitas County. There are fewer Grande Ronde water-level 

contours compared to the Saddle Mountains and Wanapum 

due to the paucity of data, and the contours also are more 

generalized in most locations and primarily are representative 

of the upper part of the Grande Ronde. Spatial and vertical 

variations in hydraulic characteristics of both individual 

flows and interbedded sediments and the presence of geologic 

structure result in a much more complex flow system for each 

unit than is depicted by the water levels.

The groundwater levels for the CRBG units show 

topographic/structural control on the movement of water 

(pl. 4) similar to that inferred for flow in the basin-fill 

deposits. The Saddle Mountains flow system is distinctly 

compartmentalized and nearly isolated in the Selah and 

Yakima basins due to both the unit’s extent and structural 

control. In the extended Toppenish basin, flow to about 

a north-south line (generally paralleling a line between 

Sunnyside and Mabton) is somewhat isolated from the Saddle 

Mountains flow system to the east. Similarly, most of the 

flow system in the Eastern Benton basin is isolated from the 

rest of the Saddle Mountains system by the Rattlesnake Hills 

structure and the Hog Ranch uplift. Flow in the Wanapum 

is similarly compartmentalized but with some connectivity 

between the Selah, Yakima, and Toppenish basins (pl. 4). 

Distinct isolation of the Wanapum flow system occurs in the 

Kittitas basin and in the areas east of the Hog Ranch uplift. 

Toppenish Ridge-Snipes Mountain also appears to be a general 

flow boundary for the Wanapum in the extended Toppenish 

basin, and the spatial extent of the flow system to the east 

is larger than that estimated for the Saddle Mountains. The 

boundary for this part of the flow system follows increased 

altitude and “flattening” of the top of the Wanapum to the 

east (Jones and Vaccaro, 2008) that approximately parallels 

the Sunnyside-Mabton boundary in the Saddle Mountains. 

However, there is a more distinct flow boundary in the 

Saddle Mountains compared to that in the Wanapum in 

the extended Toppenish basin. For example, for the 800-ft 

water-level contour, the Saddle Mountains contour along 

this boundary extends for about 10 mi to the southeast, 

whereas the Wanapum contour extends to the southeast for 

about 6 mi (pl. 4). For both units, there does not appear to 

be a large-scale regional flow system, which reflects the 

influence of the structural control. However, depending 

on the control of Snipes Mountain and its potential buried 

extension with depth, flow paths may be longer in the deeper 

parts of the Wanapum. The data are insufficient to determine 

this, however, and water-level contours were conservatively 

mapped to indicate compartmentalization. Generally, where 

both the Saddle Mountains and Wanapum are present, there 

is a reasonable correspondence in their flow systems. For 

example, groundwater levels on the north flank of Ahtanum 

Ridge-Rattlesnake Hills anticline in the Moxee subbasin show 

upgradient flexure at Konnowac Pass; the structural low at 

Konnowac Pass is where the ancestral Yakima River crossed 

the anticline (Smith, 1988).

The contours for the Grande Ronde are representative 

of the upper part of the unit because very few water 

wells penetrate more than 1,000 ft of the unit in the 

basin. Groundwater flow in the Grande Ronde also is 

compartmentalized (pl. 4) but not to the same extent as in 

either the Saddle Mountains or Wanapum. The large spatial 

extent of the Grande Ronde results in a large flow system with 

more interconnections than in the other two CRBG units, for 

example, in eastern Kittitas County and from the Selah basin 

to the Yakima basin. Where the Grande Ronde outcrops, the 

water-level contours mimic land-surface topography and they 

become a more subdued replica of topography as the unit 

becomes buried. In the more deeply buried parts of the unit, 

the contours are smoother than those for the other CRBG 

units. Similarly, water-level contours near geologic structure 

in the eastern part of the area are more subdued and smoother. 

The flow system in the Grande Ronde is controlled by the 

regional discharge locations along the Yakima and Columbia 

Rivers; that is, the regional flow (hydraulic head) in the 

Grande Ronde tends to the level of the major streams. There 

may be a regional flow system in the deeper part of the Grande 

Ronde but there are insufficient data to verify the presence 

of such a system. However, results of regional groundwater 

flow models (Hansen and others, 1994; Packard and others, 

1996) indicate the presence of a larger-scale flow system in the 

Grande Ronde that is recharged in its outcrop area to the west. 

There also may be flow contribution to the Grande Ronde 

from the underlying bedrock units.

The water-level contours also show the lateral hydraulic 

gradient in the study area. For the water table (pl. 3), the 

hydraulic gradient ranges from about 7 ft/mi in the Toppenish 

basin to more than 400 ft/mi in the Roslyn, Selah, and Eastern 

Benton basins. Close spacing of contours (steep hydraulic 

gradients) is indicative of areas with units having low Kh and 

(or) steep terrain. Kh generally is large where the spacing is 

further apart (low hydraulic gradients), such as in the central 

part of the Toppenish basin. In this area, some of the surficial 

units consist of coarse-grained deposits with Kh values on 

the order of 800 ft/d (Bolke and Skrivan, 1981). The steep 

gradients typically occur in steep terrain near narrow river 

valleys. Except for parts of the Eastern Benton basin, gradients 

are low along the major stream channels. For example, in the 

Roslyn and Kittitas basins the gradients are as small as 12 

and 17 ft/mi, respectively, along the channels. Low gradients, 

about 15–17 ft/mi, also are present along the lower Naches 

River and Wenas Creek valleys. In the Yakima basin, hydraulic 

gradients are as small as 21 ft/mi along the Yakima River. In 

the Eastern Benton basin, most gradients range from about 

70 to 200 ft/mi. To the north and east of the Yakima River 

to the Columbia River, especially north of Richland on the 
Groundwater in the Yakima River Basin 57

Hanford Site, hydraulic gradients are only about 9 ft/mi, which 

corresponds to flatter gradients in areas of deep water tables. 

In the central section of the eastern part of Badger Coulee, 

there is an area where the gradient is about 17 ft/mi, which is 

probably due to the decreasing thickness of the Touchet Beds 

and the large thickness, about 100 ft, of the coarse-grained 

Pasco gravels (Drost and others, 1997; Jones and others, 

2006). For comparison, the lateral hydraulic gradient for the 

consolidated units (pl. 1) was estimated to range from about 

15 to 50 ft/mi.

The lateral hydraulic gradient in the CRBG units also 

is highly variable (pl. 4). Similar to those in the water-table 

system, the steepest gradients are in areas of steep topography 

and the lowest gradients occur along the synclines in the 

topographically smooth parts of the structural basins. For 

example, the slope of the water-level contours for the Saddle 

Mountains and the slope of the land surface are generally 

within 5 degrees of each other over about 85 percent of the 

extent of the unit; this type of similarity was described by 

Toth (1978). This relation between hydraulic gradient and 

topographic slope also holds for the Wanapum and Grande 

Ronde. An overview of basalt lateral gradients is described on 

the basis of the Saddle Mountains water-level contours, and 

the gradients are generally representative of the other basalt 

units. The lowest hydraulic gradients occur in the Toppenish 

basin where they range from about 3 to 14 ft/mi. Low 

gradients, on the order of 7–10 ft/mi, also occur in parts of the 

Eastern Benton basin. Moderate gradients, 25–40 ft/mi, occur 

along the synclinal valley in the Yakima basin. In contrast, the 

lowest Saddle Mountains gradient in the valleys in the Selah 

basin is more than 50 ft/mi. In gently sloping uplands, such as 

in parts of the Satus Creek basin and parts of the Rattlesnake 

Hills, hydraulic gradients can be as small as 30 ft/mi. In 

steeper and more complex terrain, gradients are more than 

125 ft/mi (such as along parts of the Rattlesnake Hills) and in 

some areas they are more than 800 ft/mi (such as along ridges 

in parts of the Selah basin). Thus, lateral hydraulic gradients 

tend to be similar to the overall topographic gradient, with 

the steepest gradients generally in zones associated with 

anticlines and (or) faults, and the smallest gradients in the 

flatter structural basins. The latter also suggests that where the 

basalt flow system meets the low-gradient flow system in the 

basin-fill deposits, groundwater in the basalt moves into those 

deposits, because, although the basalt hydraulic conductivity is 

larger in the structural basins than in the steep-gradient areas, 

somewhat steeper hydraulic gradients would otherwise be 

present in the basalts underlying the basin-fill deposits. 

Groundwater moving along local-to-regional flow 

paths of varying lengths has both lateral and vertical flow 

components in a three-dimensional flow system. Depending 

on location (lateral and vertical), the movement of water may 

be predominantly downward, upward, or lateral. In large flow 

systems, flow direction is predominantly downward in the 

uplands, lateral in a transition zone, and upward in regional 

discharge locations. These three zones also are referred to 

as the zone of recharge, zone of lateral flow, and zone of 

discharge, respectively (Berger, 2000). Superimposed on these 

generalized large-scale patterns are complex variations. For 

example, for the bedrock units and Wanapum and Grande 

Ronde, high hydraulic heads in the wetter uplands compared 

to heads at lower altitudes suggest predominantly downward 

flow. However, large potential recharge quantities, limiting 

infiltration rates, and (or) lower Kh and Kv valuesin some 

areas also produce a large lateral-flow component in the 

upper part of the flow system. The lateral flow component 

follows local to intermediate flow paths to streams, and it 

can support as much as 50 percent of the streamflow during 

certain periods, especially in areas floored by bedrock units 

(Mastin and Vaccaro, 2002). In areas of regional groundwater 

discharge, which are typically along the major streams and 

near the outlets of the structural basins, flow directions are 

upward in the deeply buried confined units and transition to 

predominantly lateral in the upper part of the surficial watertable unit. For example, lateral flow is indicated in the surficial 

units in the extended Toppenish basin (pl. 3), whereas a 

flowing, 1,020-ft deep well near the Yakima River (10N/20E04L01, completed in Unit 5 of the Toppenish basin) is in an 

area of upward flow—the lateral component of groundwater 

flow is minimal in this part of the system below the river.

The direction and magnitude of the vertical component 

of flow thus varies spatially and with depth. On a regional 

basis, vertical flow is downward in the uplands and transitions 

to upward near the boundaries of the structural basins. The 

downward component can be large; for example, an 830-ft 

downward head difference was noted in a 3,200-ft section 

of the Grande Ronde unit in a test well drilled on the crest 

of Rattlesnake Mountain (Raymond and Tillson, 1968). This 

large-scale pattern is similar to that described by Hansen 

and others (1994). Locally, there are complex variations in 

the direction and magnitude of vertical flow due to geologic 

structure and the spatial variations in Kv and Kh values 

recharge, and hydrogeologic-unit composition. In turn, 

the vertical hydraulic gradient that drives the vertical flow 

integrates these variations.

To improve the understanding of vertical gradients for 

the aquifer system as a whole, non-pumping water-level 

measurements were made, where possible, in two closely 

spaced wells with different depths. Seventy-three pairs of 

wells were identified for analysis of vertical gradients. The 

vertical distance over which the water-level differences were 

assumed to be occurring was based on the well depths because 

the wells were all open at the bottom, which is representative 

of the maximum opening depth. The difference in depths 

for the well pairs averaged 396 ft (median of 240 ft), with 

90 percent of the values between 53 and 975 ft; the maximum 

depth difference was 2,094 ft. The differences in depth were 

significantly correlated (correlation coefficient 0.95) to 

the deeper well of the well pair. That is, deeper wells were 

associated with larger differences in depth, and thus, gradients 

were calculated over larger vertical distances. The median 

water-level difference for the pairs was about 35 ft and ranged 

from -174 (negative values indicate upward flow) to 485 ft; 
58 Hydrogeologic Framework of the Yakima River Basin Aquifer System, Washington

the median of the absolute water-level difference was 80 ft. 

Vertical hydraulic gradients (in units of ft/ft) ranged from 

-1.45 to 3.28 and the median was 0.16 (median of 0.32 for 

absolute values) with a standard deviation of 0.71 (0.63 for 

absolute values). Eighteen of the pairs had negative gradients 

(upward flow), 6 pairs had gradients that were near neutral 

(generally because the errors of the measurements were 

greater than the calculated gradients and (or) both wells were 

in either a zone of lateral flow or a transition zone), and the 

remaining pairs had positive gradients (downward flow). 

Considering that (1) the well pairs were widely distributed, 

representative of numerous hydrogeologic units (including 

CRBG units), and in locations ranging from recharge areas to 

regional discharge areas, and (2) the difference in depths of 

the pairs of wells was as much as 2,094 ft, the consistency of 

vertical hydraulic gradients (fully 75 percent of the absolute 

values were less than 0.51) was unexpected. Most of the 

variation in vertical gradients occurred for differences in 

depths for pairs of wells that were less than 201 ft (median 

gradient of 0.36 for 34 absolute values) compared to openingdepth differences greater than 200 ft (median gradient of 

0.30 for 39 absolute values); the range in gradients for the 

less than 201-ft category was more than 4 times the range for 

the greater than 200-ft category. These differences suggest 

that (1) the shallow part of the flow system is more active 

than the deeper part, and (2) the deeper system approaches 

equilibrium, probably due to base level water-level altitudes 

in the regional discharge areas and minimal effects from 

recharge. Depth differences also were significantly related (at 

the 0.01 significance level) to the vertical hydraulic gradient 

and the slope of the relation was negative—the deeper in the 

system the higher the probability of upward vertical gradients. 

Whiteman and others (1994) present basalt water-level 

hydrographs from piezometers in the Columbia Plateau aquifer 

system that show vertical hydraulic gradients ranging from 0.2 

to 0.54. Packard and others (1996) estimated vertical gradients 

of 0.14 in the Wanapum along the axis of Horse Heaven Hills 

and identified previous work that calculated values of 0.18 for 

the Saddle Mountains in the same area, further suggesting that 

the vertical gradients in the CRBG units fall in a relatively 

narrow range. In one area in Texas for the Gulf Coast aquifer 

system, Williamson and Grubb (2001) report vertical gradients 

of 0.15 and 0.16. Vaccaro and others (1999) report vertical 

gradients ranging from 0.01 to 0.36 (average of 0.30) for the 

Puget Sound aquifer system; the lower value was for coarsegrained, alluvial valley water-table systems. Woodward and 

others (1998) report vertical gradients ranging from 0.02 to 

0.13 for the Willamette Lowland aquifer system. Together, this 

information suggests that vertical gradients approach some 

equilibrium value that may be independent of a particular 

regional flow system, regardless of location within the 

system. Variations to the above aspect are found in confined 

units with high artesian pressure, further indicating that the 

magnitude of the vertical gradients is a function of the degree 

of confinement. 

On the basis of water levels noted on driller’s logs, 

data from piezometers, and logging of wells, water-level 

changes with depth can be abrupt for basalt wells, and indicate 

complex variations in vertical gradients. Packard and others 

(1996) describe and present examples of this for the Horse 

Heaven Hills. As an example of this phenomenon, the largest 

vertical gradient was observed in the USGS Medicine Valley 

observation well (11N/16E-15K01P1 and -15K01P3, both 

completed in the Grande Ronde). P3 is open at a depth of 

525 ft and its water level is about 12 ft below land surface, and 

P1 is open at 674 ft and its water level is about 500 ft below 

land surface—indicating an abrupt water-level change due to 

a low-permeability layer between 525 and 674 ft. In addition, 

water levels in P1 have declined more than 50 ft since 1972, 

whereas water levels in P3 have declined by only about 3 ft. 

It is of interest that there is no pumping upgradient of the 

observation well and the nearest groundwater irrigation is 

several miles away, indicating the lower zone (in which P1 is 

completed) is well connected to a downgradient pumping zone 

and that the effects of the pumping are likely due to changes 

in storage. Gregg and Laird (1975) describe how this deeper 

water-producing zone is continuous under the structure (an 

anticline) that separates Medicine Valley (a syncline) from 

the Wapato syncline to the east. The shallower P3-zone has 

water levels that are similar to those in the unconsolidated 

deposits, and this zone is not continuous through the ridge 

(Gregg and Laird, 1975). As another example of abrupt 

changes in water levels with depth, during drilling of two deep 

wells (12N/17E-16R01, 1,075-ft deep, and 11N/16E-25Q01, 

1,100‐ft deep) water levels initially indicated downward flow, 

with an abrupt transition to upward flow at depth. At well 

16R01, the flow was downward to 788 ft, reversed abruptly 

to upward, and then the well flowed from 851 to 1,075 ft. 

Similarly, the depth to water was 71 ft at 242 ft for 25Q01, 

declined to 214 ft at 880 ft, and rose to 64 ft at 1,020 ft. Well 

9N/23E-26M01 (960-ft deep) had downward flow to 829 ft 

that reversed to upward flow at 858 ft. Also, in some sections 

in 10N/23E, various basalt wells have cascading water, 

indicating a large downward gradient and low Kh value for the 

flow interiors. 

When groundwater moves in the three-dimensional flow 

system from recharge areas to discharge areas, the water 

moves between hydrogeologic units, and there are both 

losses and gains of water to a unit. On a long-term basis and 

under natural conditions, the losses from and gains to a unit 

would be approximately the same because the groundwater 

flow system is approximately in equilibrium. Under current 

conditions, groundwater pumpage and increases in recharge 

have changed both the quantities and directions in the 

movement of water between all units (Skrivan, 1987; Hansen 

and others, 1994; Bauer and Hansen, 2000). Water-level 

hydrographs for wells 12N/21E-16L01 (1,390 ft deep, cased to 

1,017 ft, completed in Wanapum) and 12N/21E-16N02 (704 ft 

deep, open to 640–704 ft, completed in Saddle Mountains) 

(fig. 21B) in the upper Moxee subbasin illustrate how these 
Groundwater Use 59

changes occur due to pumpage. From about 1979 to 1981, 

differences in water levels between these two wells were 

about 275 ft, with the deeper well (12N/21E-16L01) having 

higher water levels, indicating an upward vertical gradient. 

The water level in 16L01 during this period was more than 

500 ft above the top of the Wanapum. By 1997, that difference 

had been reduced to about 94 ft—a reduction in the vertical 

gradient from about -0.88 to -0.30. As a result, the upward 

movement of groundwater in this area may have decreased by 

about 76 percent between 1979 and 1997. If the downward 

trend in water levels of about 11.6 ft/yr has continued in 

16L01, the water-level difference in 2000 may have been 

less than 60 ft and by 2005 there may have been a reversal in 

flow direction, from upward to downward. However, water 

levels in nearby wells completed in the Saddle Mountains 

have declined similar to levels in the Wanapum in well 16L01, 

and the vertical gradients remain upward. Thus, a reversal to 

downward vertical gradients may be confined to this particular 

area.

Water-level data and flow-system analyses indicate 

that the movement of water between and within basalt flows 

decreases with increasing age of the basalt due to overburden 

pressure (Hansen and others, 1994; Reidel and others, 2002) 

and secondary mineralization; the latter was documented by 

geochemical information (Ames, 1980; Benson and Teague, 

1982; Hearn and others, 1985; Steinkampf and Hearn, 1996). 

As a result, vertical movement of groundwater between basalt 

flows in the Saddle Mountains and Wanapum units generally 

is less impeded than the movement between either Grande 

Ronde flows or between the Wanapum and Grande Ronde 

units. Thus, lateral water movement in the Grande Ronde, 

where it is deeply buried, is less than the other basalt units 

due to fracture infilling from secondary mineralization and 

overburden pressure; this aspect is especially true where there 

is large thickness of the Grande Ronde such as in the Eastern 

Benton basin. Where the Grande Ronde outcrops, it functions 

similar to the other basalt units in their outcrop areas. 

Depending on their hydraulic characteristics, interbeds in the 

basalts can cause either increased or decreased movement 

of groundwater between basalt flows. In some areas (for 

example, in 10N/23E in the Rattlesnake Hills), some highyield irrigation wells obtain their water from the interbeds 

because locally they are more productive than the CRBG 

units. In other areas, for example in 13N/24E, the Mabton 

Interbed is composed of shale and sandstone and acts as a 

confining unit.

No data are available on the vertical movement of water 

in the bedrock units. However, on the basis of information for 

similar rock types and of similar ages elsewhere, the vertical 

movement would be greatly diminished with depth (Hollyday 

and Hileman, 1996). For example, in parts of Kittitas County 

with a large potential recharge rate, depths to water in many 

wells range from 150 ft to more than 400 ft, suggesting lower 

Kv values because large potential recharge rates are generally 

associated with a shallow water table.

Groundwater Use

Vaccaro and Sumioka (2006) estimated groundwater 

pumpage from the aquifer system for the period 1960–2000 

for eight categories of use, and they estimated that more 

than 40,000 water wells withdrew about 312,284 acre-ft 

(about 430 ft3/s) in 2000 for multiple uses and averaged 

about 234,000 acre-ft (about 325 ft3/s) during that 41-year 

period; these quantities exclude estimates for standby/

reserve irrigation pumpage. The 8 categories of use were: 

(1) municipal, including two larger Washington State 

Department of Health Group A systems (Terrace Heights and 

Nob Hill), and some systems operated by Yakima County, 

(2) irrigation, (3) commercial and industrial, (4) livestock, 

(5) fish and wildlife, (6) non-municipal Group A and B 

systems, (7) domestic, and (8) groundwater claims. Group A 

systems generally have 15 or more service connections and 

Group B systems generally have 2 to 14 connections. The first 

5 categories (especially category 2) account for most of the 

2,874 active groundwater rights in the study area; categories 

6 and 7 also include some groundwater rights. The irrigation 

category includes standby/reserve rights. These rights were 

obtained by surface-water users in irrigation districts with 

proratable surface-water rights, and the wells would be 

pumped during prorating years. The total allowable quantities 

for the groundwater rights (certificates and permits) as of 2001 

were (R. Dixon, Washington State Department of Ecology, 

written, commun., 2001):

Number of 

certificates 

and permits

Entitlement Irrigated 

area 

(acres)

Instantaneous 

(gal/min)

Annual

(acre-ft)

Certificates 2,575 720,683 422,040 101,371

Permits 299 230,623 107,191 28,199

The estimates of pumpage for 1960–2000 (table 5; 

Vaccaro and Sumioka, 2006) show that the irrigation category 

accounts for about 60 percent of the total pumpage without 

standby/reserve estimates. However, it was estimated that 

about 32,430 acre-ft of the pumpage for the groundwater 

claims category (95 percent of the total) was for irrigating 

about 12,800 acres, indicating that about 70 percent of the 

312,284 acre-ft of pumpage in 2000 was for irrigation. The 

information in table 5 indicates that the pumpage in 2000 for 

the non-irrigation categories falls within two general ranges, 

values less than 9,369 acre-ft and values ranging from 20,036 

to 37,272 acre-ft. The total for the Public Water Supply 

(including municipal) and domestic categories was about 

66,421 acre-ft or about 21 percent of the total (table 5).
60 Hydrogeologic Framework of the Yakima River Basin Aquifer System, Washington Table 5. Summary of estimated annual pumpage, by pumpage category in 5-year increments, Yakima River basin, Washington, 1960–2000. [Data from Vaccaro and Sumioka (2006). Public water supply: Pre-1960 includes some pumpage for 1960 because initial estimates were calculated for 1960 for Group A and B systems, and domestic. Irrigation Standby/reserve: Estimates based on pumpage that occurred in all years and is not the actual pumpage; pumpage occurred only in 1977, 1979, 1987, 1988, 1992, 1993, and 1994. Groundwater claims: About 95 percent of pumpage for claims is for irrigation. Cumulative: cumulative is total pumpage at end of time period and does not include standby/reserve estimates. Total pumpage for each category and for all categories combined is for 2000. Estimates based on pumpage that occurred in all years and are not the actual pumpage; estimates for total annual pumpage existing prior to 1960 are also shown. All values in acre-feet] Years Public water supply Domestic Irrigation Livestock Commercial and industrial Fish and wildlife Ground- water claims Total for all categories Cumulative without standby/ reserve Municipal Group A systems Group B systems Total Primary Standby/ reserve Pre-1960 19,127 3,888 858 12,379 42,000 41,896 104 222 3,093 3 34,310 115,880 115,776 1960–64 628 331 73 1,187 9,299 9,299 0 208 438 0 0 12,164 127,940 1965–69 2,702 358 79 716 20,271 20,249 22 39 1,428 0 0 25,593 153,511 1970–74 1,379 389 85 988 25,010 23,743 1,267 3,189 612 2 0 31,654 183,898 1975–79 4,236 422 93 2,914 99,474 49,399 50,075 84 44 58 0 107,325 241,148 1980–84 975 458 101 -107 28,845 17,507 11,338 996 1,442 2,661 0 35,371 265,181 1985–89 2,614 586 110 305 20,687 14,927 5,760 461 170 0 0 24,933 284,354 1990–94 1,793 449 119 1,175 21,821 10,398 11,423 1,527 3 4,194 0 31,081 304,012 1995–2000 3,819 584 129 479 3,635 812 2,823 0 0 2,451 0 11,097 312,286 Cumulative through 2000 37,273 7,465 1,647 20,036 271,042 188,230 82,812 6,726 7,230 9,369 34,310 395,098 312,286
Groundwater Use 61

The standby/reserve irrigation pumpage was estimated 

by Vaccaro and Sumioka (2006) as if every year was an 

extreme drought year (that is, how much would be pumped if 

there were no surface water available). These estimates were 

intended to provide information for long-term planning related 

to how much withdrawals could occur in the basin. Thus, 

the estimates represent what could have been pumped for an 

existing crop type but not what was actually pumped; these 

values are reported in table 5 and indicate the total potential 

pumpage for irrigation for these rights. The prorating years 

with standby/reserve pumpage were 1977, 1979, 1987, 1988, 

1992, 1993, 1994, 2001, and 2005: the prorating level for 

1973 (the first year of prorating) was 80 percent, and standby/

reserve pumpage was not implemented to any extent (J. Kirk, 

Washington State Department of Ecology, oral commun., 

2005). Note that only estimates of standby/reserve pumpage 

through 2001 are being used in other work elements of this 

study. Based on the methods outlined by Vaccaro and Sumioka 

(2006), standby/reserve pumpage was estimated to have 

ranged from about 9,200 acre-ft in 1988 to 52,100 acre-ft in 

1994 and 2001, and total standby/reserve pumpage for the 8 

prorating years through 2001 was about 250,350 acre-ft. 

All pumpage values except standby/reserve reported by 

Vaccaro and Sumioka (2006) for 2000 and, where available, 

for 2001, were aggregated by one-quarter township-range in 

order to provide a map that shows the spatial distribution of 

most of the groundwater pumpage in the basin. It was assumed 

that for wells with no estimates for 2001, the pumpage in 2001 

was similar to that in 2000. The estimated domestic pumpage 

for each census block was aggregated to the quarter townshiprange based on the location of the centroid of a census block. 

In addition, the standby/reserve pumpage for 2001 (the 

52,100 acre-ft described above) also was added. Thus, the 

map of aggregated pumpage (fig. 22) presents an estimated 

distribution of pumpage during the major drought year of 

2001. The spatial scale of the aggregation did not allow for 

showing all of the estimated pumpage on the map due to 

source-water security concerns.

Most of the pumpage in 2001 was in the lower part of 

the basin (fig. 22), especially in Yakima County, which is also 

the location of most of the groundwater rights, groundwater 

claims, and population. The least pumpage occurred in Kittitas 

County, the least populous county in the study area and the 

county with the smallest number of groundwater rights. 

The pumpage occurs from all of the aquifers in the aquifer 

system. About 48 percent of the pumpage was from the units 

composed of basin-fill sediments, 50 percent from the CRBG 

units, and 2 percent from the bedrock units; these percentages 

include pumpage in the extended study area.

The cumulative pumpage for the 1960–2001 base period 

is of interest for comparison with historical groundwater 

levels. The cumulative pumpage from the system was 

estimated to be about 10 million acre-ft and its spatial 

distribution (fig. 23) generally is similar to that of 2001 

pumpage; differences in the spatial distribution are due 

to the timing of the growth in pumpage. Areas where the 

cumulative pumpage was large and groundwater levels were 

stable indicate large quantities of recharge and (or) a large 

groundwater source (contributing) area. In contrast, areas 

where the cumulative pumpage was large and groundwater 

levels declined indicate limited quantities of recharge and (or) 

a small source area. These relations will be discussed in more 

detail in the following section. 

Although the information shown in figures 22 and 23

indicates the magnitude of pumpage, it does not show the 

total allowable pumpage—the total entitlements as of 2001 

shown previously. The unused, allowable water-right pumpage 

(including that from exempt wells) and the requested pumpage 

in existing (as of 2001) applications for new groundwater 

rights are nearly twice the estimated pumpage in 2001. 

Requested instantaneous rates for applications totaled about 

613,306 gal/min and the applications were for a total irrigated 

acreage of 64,308 acres.

In comparison to groundwater use, the surface-water 

use in the basin, as measured by diversions, is much greater. 

This aspect of water use is important for improving the 

understanding of the relation between the effects of the flow 

and diversion of surface water and groundwater pumpage on 

the aquifer system. Mean annual discharge and time-series of 

monthly discharge for surface-water diversions were estimated 

on the basis of data obtained from several sources; however, 

the mean annual values from the different sources are not 

precisely comparable (see appendix D). Note that time series 

of monthly estimates are needed for other parts of this study, 

in particular for the groundwater flow models. The estimated 

mean annual discharge for surface-water diversions, which 

are principally from the Yakima and Naches Rivers, shows 

the magnitude of the diversions (fig. 24). Most of the diverted 

surface water is accounted for by 65 diversions (fig. 24, 

Reclamation-based information; appendix D) and to a lesser 

extent by the diversions that were aggregated to 78 points 

of withdrawal (fig. 24, WaDOE- and YN-based information; 

appendix D). The distribution of diversions throughout the 

basin reflects the history of water development in the basin 

because almost all of the diversions were established before 

1920.

Mean annual discharge (for water years 1960–2001) for 

the 65 diversions was about 5,860 ft3/s (or about 4.2 million 

acre-ft), and values for individual diversions ranged from 

about 1 to 1,031 ft3/s. About 1,950 ft3/s of this diverted water 

was returned as power-generation returns (Roza, Wapatox, 

and Chandler power plant returns), yielding about 3,910 ft3/s 

for other uses (principally irrigation). The total for the other 

78 points of withdrawals was 474 ft3/s (or about 0.3 million 

acre-ft—about equivalent to the groundwater pumpage in 

2001), and the values ranged from about 0.1 to 39 ft3/s. 

Together, the non-power quantities total 4,383 ft3/s, or about 

10 times greater than the estimated pumpage in 2000. About 

69 percent of the diverted water was for irrigation, 31 percent 

was for power generation, and less than 1 percent was for 

municipal supply.
62 Hydrogeologic Framework of the Yakima River Basin Aquifer System, Washington

Figure 22. Spatial distribution of pumpage from the Yakima River basin aquifer system, Washington, 2001.

wa19-0148_YakimaGW_Fig.22-Pumpage

121°30' 121° 120°30' 120° 119°30'

47°

46°30'

47°30'

46°

0

1 to 50

51 to 450

451 to 1,000

1,001 to 3,000

3,001 to 6,000

6,001 to 9,279

Annual pumpage, in acre-feet;

 block size is one-quarter township

EXPLANATION

3020100 40 KILOMETERS

0 10 20 30 40 MILES

Bumping

Lake

S Fk

N Fk

Cle Elum River

Bumping River

Ahtanum Creek

Tieton River Wenas Creek

North Fork

Dry Creek

Creek

Toppenish

RIVER

YAKIMA

Satus

Creek

Cle

Elum

Lake

Rimrock

Lake

Kachess Lake

Keechelus Lake

Lake

Wallula

Teanaway River

Umtanum Creek

Little Naches River

Cowiche Creek

Cowiche Creek

River

Naches

RIVER

YAKIMA

RIVER

YAKIMA

Sunnyside Richland

Yakima

Ellensburg

T.

25

N.

T.

23

N.

T.

21

N.

T.

19

N.

T.

17

N.

T.

15

N.

T.

13

N.

T.

11

N.

T.

9

N.

T.

7

N.

T.

5

N.

R.11E. R.13E. R.15E. R.17E. R.19E. R.21E. R.23E. R.25E. R.27E. R.29E.
Groundwater Use 63

wa19-0148_YakimaGW_Fig.23-Pumpage-cumulative

0

1 to 5,000

5,001 to 20,000

20,001 to 50,000

50,001 to 100,000

100,001 to 150,000

150,001 to 348,895

Cumulative pumpage, in acre-feet;

 block size is one-quarter township

EXPLANATION

3020100 40 KILOMETERS

0 10 20 30 40 MILES

Bumping

Lake

S Fk

N Fk

Cle Elum River

Bumping River

Ahtanum Creek

Tieton River Wenas Creek

North Fork

Dry Creek

Creek

Toppenish

RIVER

YAKIMA

Satus

Creek

Cle

Elum

Lake

Rimrock

Lake

Kachess Lake

Keechelus Lake Teanaway River

Umtanum Creek

Little Naches River

Cowiche Creek

Cowiche Creek

River

Naches

RIVER

YAKIMA

RIVER

YAKIMA

Sunnyside

Yakima

Ellensburg

T.

25

N.

T.

23

N.

T.

21

N.

T.

19

N.

T.

17

N.

T.

15

N.

T.

13

N.

T.

11

N.

T.

9

N.

T.

7

N.

T.

5

N.

R.11E. R.13E. R.15E. R.17E. R.19E. R.21E. R.23E. R.25E. R.27E. R.29E.

121°30' 121° 120°30' 120° 119°30'

47°

46°30'

47°30'

46°

Figure 23. Spatial distribution of cumulative pumpage from the Yakima River basin aquifer system, Washington, 1960–2001.
64 Hydrogeologic Framework of the Yakima River Basin Aquifer System, Washington

Figure 24. Location and estimated mean annual quantity of surface-water diversions in the Yakima River basin, Washington.

WA_0148_Yakima GW-Fig 24-Diversions

KITTITAS COUNTY

YAKIMA COUNTY

COUNTY

BENTON COUNTY

KLICKITAT

COUNTY

YAKIMA

Bumping

Lake

S Fk

N Fk

Cle Elum River

Bumping River

Ahtanum Creek

Tieton River

Wenas Creek

North Fork

Dry Creek

Simcoe

Creek

Toppenish

Creek

RIVER

YAKIMA

Satus

Creek

Cle

Elum

Lake

Rimrock

Lake

Kachess Lake

Keechelus Lake

Lake

Wallula

Teanaway River

Umtanum Creek

Little Naches River

Cowiche Creek

North Fork

River

Naches

RIVER

YAKIMA

RIVER

YAKIMA

Nile Creek

Rattlesnake Cr

N Fk

Carmack

Creek

Cle Elum

Parker

Wapato

Ellensburg

Umtanum

Kittitas

Thrall

Toppenish

Moxee City Union Gap

Yakima

Selah

Naches

Sunnyside Richland

Kiona

Kennewick Prosser

Grandview

Mabton

Satus

Zillah

Granger

Roza

Easton

Teanaway

Tieton Rimrock

Snoqualmie

Pass

Van Epps

Pass

Esmeralda

Peaks

K I T T I T A S

V A L L E Y

M A N A S T A S H

KACHESS RIDGE

R I D G E

UNION GAP

CLEMAN

MOUNTAIN

TEANAWAY

NORTH RIDGE

U M T A N U M

R I D G E

Deception

Pass

Y A K I M A

 V A L L E Y

AHTANUM RIDGE

COWICHE MTN

AMERICAN RIDGE

CLE ELUM

RIDGE

RIDGE

TOPPENISH RIDGE

R A T T L E S N A K E H I L L S

Y A K I M A R I D G E

H O R S E

H E A V E N

H I L L S

C

A

S C A

D E R

A

N

G

E

W E N AT C H E E

M O U N TA I N S

Gilbert

Peak

121°

47°

47°

30'

46°

121°30' 120°30' 120° 119°30'

46°

30'

0 5 10 20 30 40 MILES

0 5 10 20 30 40 KILOMETERS

EXPLANATION

Mean annual diversions, in cubic feet per second

0.3 to 20.0

20.1 to 40.0

1 to 20

21 to 60

61 to 150

151 to 550

551 to 1,172

ENTITLEMENT

(Washington Department

of Ecology)

OBSERVED or ESTIMATED

(Bureau of Reclamation)

T.

24

N.

T.

22

N.

T.

20

N.

T.

18

N.

T.

16

N.

T.

14

N.

T.

12

N.

T.

10

N.

T.

8

N.

T.

6

N.

R.10E. R.12E. R.14E. R.16E. R.18E. R.20E. R.22E. R.24E. R.26E. R.28E.

Water-Level Trends

Trends in groundwater levels are one of several factors 

important to understanding groundwater availability. Trends, 

and absence of trends, when analyzed in conjunction with 

groundwater pumpage, streamflow, and recharge, can indicate 

areas where there have been: (1) changes in groundwater 

storage, (2) potential capture of recharge, and (3) changes 

in groundwater discharge to streams, springs, or wetlands. 

Pumpage (discharge by wells) must be balanced by one or a 

combination of the above three changes (Theis, 1940).

In order to assess trends, water-level data stored in 

NWIS were analyzed. These data include water levels entered 

into the database during this study that were obtained from 

older reports and field sheets, and measurements made by 
Water-Level Trends 65

(1) the USGS between 2000 and 2002, (2) the WaDOE 

between 1986 and 2002, (3) the YN between 1993 and 

2002, and (4) Reclamation between 2000 and 2002. A total 

of about 300 wells were identified for which some waterlevel measurements that spanned at least a 10-year period. 

Most wells selected for trend analysis were measured in the 

mid-1990s to 2000–02 (the latter period is when personnel 

from Reclamation, USGS, WaDOE, and YN measured water 

levels); this selection yielded more than 220 wells. A few 

wells with measurements that did not span 10 years also 

were included in the analysis for areas or units with limited 

historical data. The lengths of the records vary and, thus, 

the long-term trends may be more or less than the trend 

indicated in the measurement period. The selected wells have 

a reasonable spatial distribution and are a subset of wells that 

met the criteria. The hydrographs for the final subset of wells 

were published as an interactive World Wide Web report (Keys 

and others, 2008). 

Groundwater-level trends were categorized as: stable 

to small water-level declines (0–20 ft), moderate declines 

(21–75 ft), large declines (76–150 ft), and very large declines 

(greater than 150 ft). Each category does not include wells 

completed in all of the water-producing hydrogeologic units 

because there was either a paucity of long-term data or there 

were no declines of a particular magnitude for a unit. A few 

wells exhibited upward trends in water levels and these are 

discussed separately. Where data permitted, areas and units 

were identified that had water-level trends for these categories 

and maps were constructed. The maps were constructed 

conservatively in that the mapped extent for any particular 

category of declines was kept to a minimum. The maps show 

the long-term spatial trends in groundwater levels. Example 

hydrographs for each category are presented and discussed 

below.

Stable to small declines in water levels (0–20 ft) are 

exemplified by four wells (fig. 25A-D) in areas with small 

rates of pumpage, large recharge rates, and (or) large 

upgradient source areas. Well 9N/21E-16D01 (fig. 25A) is 

completed in Unit 2 in the extended Toppenish basin and 

nearby well 9N/21E-26M01 (fig. 25B) is completed in the 

Saddle Mountains and Wanapum. The small decline for 

9N/21E-16D01 is associated with large quantities of recharge 

(the well is in WIP). In contrast, the small decline in 9N/21E26M01 is associated with small rates of pumpage in this 

area from these units, combined with a large, upgradient 

groundwater source area. If the declining water level for 

26M01 continued through 2008 (assuming the pumpage 

remained the same), the total decline would still likely be less 

than 20 ft. Well 11N/19E-10A02 is completed in Units 2 and 

3 in the Toppenish basin and the small decline (fig. 25C) is 

associated with low rates of pumpage from these units and a 

large groundwater source area in this location of upward flow. 

Finally, well 17N/20E-29R01 (completed in Unit 3 of the 

Kittitas basin) shows little or no decline with a distinct springfall difference in water levels (fig. 25D). Pumpage rates are 

small in this part of Unit 3 in this area.

Moderate declining water levels (21–75 ft) are 

exemplified by four wells in areas with low to moderate rates 

of pumpage, moderate to large recharge rates, and (or) large 

upgradient source areas (fig. 26A-D). Well 10N/16E-15N01 

(fig. 26A) is completed in the Grande Ronde in the Toppenish 

basin, and declines are moderated because pumpage rates 

in this unit are not as large as in some other areas/units 

(for example, pumpage from the Wanapum and Saddle 

Mountains to the east and north of this area in the western 

Toppenish basin), the unit receives recharge in its large 

outcrop area (fig. 8, pl. 2), and its upgradient area receives 

recharge quantities of more than 10 in/yr. However, nearby 

large downward trends are noted in both the Wanapum and 

Saddle Mountains. The moderate decline for well 10N/21E03H01 (fig. 26B; completed in the Saddle Mountains) is due 

to low rates of nearby pumpage. A moderate decline also is 

indicated by the hydrograph for Wanapum well 13N/17E04D02 in the Selah basin (fig. 26C). Nearby pumpage irrigates 

about 400 acres of lands, but the overall small quantity of 

withdrawals in this area and the size of the upgradient source 

area moderates the declines. Similarly, declines in well 

14N/18E-19L01 (fig. 26D; completed in the Wanapum) also 

are moderated due to its large source area and small rates of 

nearby pumpage.

Large downward trends in water levels (76-150 ft) 

(fig. 27A-E) have been observed primarily in deep CRBG 

wells in areas with large rates of pumpage, including 

standby/reserve pumpage. For example, water levels in well 

10N/17E-27Q01 (open to all three CRBG units) display a 

continual downward trend over a 43-year period—a decline of 

about 2.9 ft/yr (fig. 27A). In a 1,100-ft deep Wanapum-Grande 

Ronde composite well (11N/16E-25Q01), water levels also 

show a steady decline that averages about 2.7 ft/yr (fig. 27B); 

a seasonal hydrograph for this well (inset on fig. 27B) shows 

the steady decline after each irrigation season. Water-level 

declines in Saddle Mountains-Wanapum composite wells 

12N/18E-32H01 and -32L01 (fig. 27C) indicate a consistent 

and nearly linear large decline in this area. A Wanapum 

well (14N/17E-04H02, 1,000 ft deep) experienced a 94-ft 

decline over a 49-year period—about 1.9 ft/yr (fig. 27D). 

However, most of the decline started in about 1987–88 

during a 2-year drought period. Hydrographs from other 

wells also display an onset of declines during the 1987–88 

drought period, especially CRBG wells in areas with standby/

reserve irrigation pumpage (see Keys and others [2008] 

for hydrographs with similar onsets of declines). Effects of 

droughts on water levels due to both increased pumpage 

and reduced recharge are well documented. For example, of 

the 460 wells that were measured during this study in both 

the spring of 2001 (a major drought year) and the spring of 

2002, about 66 percent had water-level declines during this 

period. In addition to deep CRBG wells, water levels in well 

20N/15E-28Q04 (completed in the confined aquifer-Unit 

3 in the Roslyn basin) display a large downward trend due 

to pumpage (fig. 27E). This large decline occurred because 

limited recharge reaches the unit through either overlying 
66 Hydrogeologic Framework of the Yakima River Basin Aquifer System, Washington

Figure 25. Examples of groundwater level hydrographs with stable or small 

declines, Yakima River basin, Washington.

WA_0148_fig25-Hydrograph_stable

19781980198219841986198819901992199419961998200020022004

5

10

15

DEPTH TO WATER, IN FEET

09N/21E-16D01 Well depth 130 feet

197019721974197619781980198219841986198819901992199419961998200020022004

Land Surface

-5

0

5

DEPTH TO WATER, IN FEET

09N/21E-26M01 Well depth 960 feet 1978 1980 1982 1984

1986198819901992199419961998200020022004

30

40

50

60

70

90

80

100

DEPTH TO WATER, IN FEET

17N/20E-29R01 Well depth 400 feet

DEPTH TO WATER, IN FEET

11N/19E-10A02 Well depth 765 feet 1970 1972 1974 1976 1978 1980 1982 1984

1986198819901992199419961998200020022004

10

15

20

25

30

5

35

A.

B.

C.

D.
Water-Level Trends 67

WA_0148_fig26-Hydrograph_moderate

14N/18E-19L01 Well depth 1,009 feet 230

240

250

260

270

280

290

310

300

DEPTH TO WATER, IN FEET

197819801982198419861988199019921994199619982000

20022004

13N/17E-04D02 Well depth 452 feet

20

30

40

50

60

70

DEPTH TO WATER, IN FEET

198019821984198619881990199219941996199820002002

2004

10N/21E-03H01 Well depth 775 feet

60

70

80

90

100

110

120

130

140

150

DEPTH TO WATER, IN FEET

19761978198019821984198619881990199219941996199820002002

2004

10N/16E-15N01 Well depth 310 feet 60

70

80

90

100

110

120

DEPTH TO WATER, IN FEET

1954

195619581960

19621964

1966196819701972

1974

197619781980

19821984

1986

1988

1990

1992

199419961998

2000

20022004

A.

B.

C.

D.

Figure 26. Examples of groundwater level hydrographs with moderate declines, 

Yakima River basin, Washington.
68 Hydrogeologic Framework of the Yakima River Basin Aquifer System, Washington

WA_0148-fig27_Hydrograph_Large

150

170

190

1962196419661968197019721974197619781980198219841986198819901992199419961998200020022004

230

190

250

270

290

310

330

350

210

19601962196419661968197019721974197619781980198219841986198819901992199419961998200020022004

90

50

110

130

150

170

190

70

1996

1998

20002002

2004

70

30

90

110

130

140

170

50

195219541956195819601962196419661968197019721974197619781980198219841986198819901992199419961998200020022004

DEPTH TO WATER, IN FEET

DEPTH TO WATER, IN FEET

DEPTH TO WATER, IN FEET

DEPTH TO WATER, IN FEET250

260

270

280

290

330

310

320

330

240

19701972197619781980198219841986198819901992199419961998200020022004

A. 10N/17E-27Q01 Well depth 1,510 feet

B.

C.

D.

E. 20N/15E-28Q04 Well depth 225 feet

14N/17E-04H02 Well depth 1,000 feet

11N/16E-25Q01 Well depth 1,100 feet

210

250

210

270

290

310

330

230

190

DEPTH TO WATER, IN FEET

12N/18E-32H01 Well depth 1,176 feet 12N/18E-32L01 Well depth 1,252 feet

 

1970 1971 1972 1973

240

250

260

 

Seasonal

Figure 27. Examples of groundwater level hydrographs with large declines, Yakima River basin, Washington.
Water-Level Trends 69

units (general flow direction is upward) or underlying lowconductivity bedrock units (the Roslyn Formation)—the 

pumpage from the wells in this particular area is larger than 

the amount of water that can replenish the unit. That is, there 

is no water to capture from rejected recharge and very little 

water to capture from groundwater discharge, so that pumpage 

is met by changes in storage.

Very large downward trends in water levels (greater than 

150 ft) (fig. 28A-D) have mainly been observed in deep wells 

in areas of intensive pumpage, limited recharge, and (or) small 

upgradient source areas. Similar to wells with large waterlevel declines, these deep wells are completed in the CRBG 

units. The 1,505-ft deep well 11N/20E-01E01 (a Saddle 

Mountains-Wanapum composite well) displays about a 150-ft 

decline over a 15-year period or about 10 ft/yr (fig. 28A). If the 

average rate of decline continued through 2008, the long-term 

decline would have exceeded 300 ft. Very large declines are 

displayed by the hydrographs for Wanapum wells 12N/22E21J01 and -21R01 (1,140- and 903-ft deep, respectively) in 

the upper Moxee subbasin (fig. 28B). These wells are in an 

area of intensive groundwater pumpage and very small rates 

of recharge. Similarly, water levels for well 12N/24E-03B01 

(a 1,239-ft deep Wanapum well) in the upper Cold Creek 

drainage display very large declines (fig. 28C). Water levels in 

other deep irrigation wells in the upper Cold Creek drainage 

also have had very large declines. As a last example, water 

levels for well 13N/24E-27M01 (a 723-ft deep Wanapum 

well) in the lower Cold Creek drainage basin have declined 

about 200 ft over about 35 years, or about 5.5 ft/yr (fig. 28D).

In the upper Moxee subbasin, and the Black Rock, Dry, 

and Cold Creek drainages, the Yakima Ridge and Rattlesnake 

Hills exert structural control on the flow system to limit 

the area of recharge to the groundwater basin. This area is 

further separated in an east-west direction by the Hog Ranch 

structure (fig. 8). Thus, groundwater flow from the north and 

south into this area is limited (except perhaps in the deeply 

buried parts of the Grande Ronde), and flow between the 

Moxee subbasin and the other drainages is limited by the 

structures (flow barriers that act as a groundwater divide). 

Historical groundwater levels in the basalts east of the Hog 

Ranch structure were typically 100–200 ft lower than levels 

west of the structure; currently, the water levels to the east 

are about 200–300 ft lower due to the effects of pumpage. In 

addition, the rate of water-level decline east of the structure 

(with less total pumpage) is much more than west of the 

structure. Recharge also is very low in these areas (fig. 16), 

and it must move downward through thick basin-fill deposits 

and (or) overlying interbeds and basalt flows. In addition, 

some of the recharge entering the upper unit(s) moves laterally 

and is not available to replenish the deeper units. As a result, 

the pumpage rates are greater than the replenishment rates 

and there have been large changes in groundwater storage. 

This also is an area for which Hansen and others (1994) and 

Bauer and Hansen (2000), using a groundwater flow model, 

estimated water-level declines on the order of 100–200 ft from 

predevelopment conditions to 1985 and projected 300–400 ft 

declines from 1985 to long-term equilibrium conditions under 

1985 pumpage (observed declines since 1985 have ranged 

from 100 ft to more than 200 ft). 

Rising water levels were observed in very few of the 

wells. The levels in both Saddle Mountains and Wanapum 

wells in Badger Coulee in the Benton basin had long-term 

rises. In addition, water levels in two of the selected wells 

completed in the Pasco gravels (toward the eastern end of 

Badger Coulee) also had long-term rises. Rises throughout 

Badger Coulee due to surface-water irrigation have been 

described by Drost and others (1997). Unlike other surfacewater irrigated areas in the basin, rises are still occurring 

because irrigation started as late as 1957 in the Kennewick 

Irrigation District and 1978 in the Badger Mountain Irrigation 

District. In comparison, irrigation started in 1893 in the 

Columbia Irrigation District. Water-level rises in the other 

surface-water irrigated areas have reached equilibrium and the 

total rise for those areas will be assessed in a subsequent part 

of this study. Water levels for well 13N/18E-24K03 (a 1,683-

ft artesian well drilled in about 1906 in an area of upward 

vertical gradient—a Saddle Mountains or Unit 3/Saddle 

Mountains composite well) in the City of Yakima showed 

a rise of about 10 ft from about 1981 through March 1993. 

However, an August 2000 water level was about 26 ft 

lower than the March 1993 reading, and a measured shut-in 

pressure of 25 lb/in2 made while conducting a field test for a 

temperature profile for the well (the actual date is unknown 

but thought to be about 1982) indicated a water level that 

was about 16 ft lower than the March 1993 reading. These 

differences may be due to seasonal variations, use of the water, 

location of the measurement line, and variations in pressuregage accuracies—an upward trend would not be expected 

for a well completed at this depth and location. Moderate 

rises in water levels (about 65 ft) were observed from 1983 

through 1991 in a 543-ft deep basalt well (16N/20E-07Q01). 

This well is just upgradient of an irrigation canal and the rises 

may be due to leakage around the borehole. Water levels from 

1991 through 2001 in this well declined during the drought 

years and rose to the 1991 level during other years. Another 

well (19N/18E-21B01, a 700-ft deep Grande Ronde well) had 

a small water-level rise of about 7 ft from 1983 through 2001; 

the reason for the rise is unknown.

Trends in groundwater levels show distinct spatial 

patterns. Rising water levels have been observed primarily 

in the Badger Coulee area in the Benton basin. Areas with 

declining water levels generally are limited to Yakima and 

Benton Counties. There also are distinct differences in waterlevel trends in the basin-fill units compared to those in the 

basalt units (no long-term data are available for the bedrock 

units). Based on available long-term water-level measurements 

for 55 wells completed in basin-fill units, only 2 areas were 

not categorized as stable (less than 21 ft of decline). Although 

continuous long-term data are not available, water-level 

declines have also occurred in the Ellensburg Formation in the 

upper Moxee subbasin; these declines are discussed below.
70 Hydrogeologic Framework of the Yakima River Basin Aquifer System, Washington

Figure 28. Examples of groundwater level hydrographs with very large declines, 

Yakima River basin, Washington. 

WA_0148_fig28-Hydrograph_verylarge 1964 1966 1968 1970

197219741976197819801982198419861988199019921994199619982000

196819701972

1974

197619781980

19821984

1986

1988

1990

1992

199419961998

2000

1994199619982000

1994199619982000

19781980198219841986198819901992

19781980198219841986198819901992

225

275

325

375

425

475

DEPTH TO WATER IN, FEET 240

290

340

390

440

490

540

DEPTH TO WATER, IN FEET

0

50

100

150

200

250

DEPTH TO WATER, IN FEET

150

200

250

300

350

400

DEPTH TO WATER, IN FEET

13N/24E-27M01 Well depth 723 feet

12N/24E-03B01 Well depth 1,239 feet

11N/20E-01E01 Well depth 1,505 feet

12N/22E-21R01 Well depth 904 feet

12N/22E-21J01 Well depth 1,130 feet

A.

B.

C.

D.
Water-Level Trends 71

One of the areas with declines in water levels in the 

basin-fill units is the Roslyn basin, where moderate to large 

declines have occurred in parts of the confined Unit 3. Unit 

3 in this area receives water principally from the underlying 

Roslyn Formation (an Eocene-age coal-rich formation—part 

of the Tertiary sediment bedrock unit) that is relatively ‘tight,’ 

and current pumpage in this part of Unit 3 is apparently larger 

than inflow from the Roslyn Formation and any capture of 

discharge. The only other basin-fill well with long-term data 

that had a moderate decline in water level was a 1,044-ft-deep 

well (13N/18E-35K01) finished in the lower part of the 

consolidated unit in the Yakima basin. The water level in 

this flowing well declined about 40 ft from 1961 to 2001. 

The water level in a nearby deep well (13N/18E-35D04 – 

1,171 ft) was categorized as stable, with a decline of less 

than 10 ft from 1995 through 2001. The total decline for this 

well may have been more than 10 ft, but measurements were 

not available from 1961 to 1995 to compare with those for 

the 1,044-ft well. This example highlights the differences in 

water-level trends based on the length of water-level records. 

The lower part of the consolidated unit in this area (Yakima 

basin) receives most of its water from the underlying Saddle 

Mountains.

In the upper Moxee subbasin, more than 30 deep wells 

were drilled from the 1890s through 1901 (Smith, 1901). All 

of these wells tapped a flowing artesian zone in the Ellensburg 

Formation (the consolidated unit in the Yakima basin, see 

table 2). Smith reported that several of the most eastward of 

the wells had stopped flowing by 1901. A 1982 WaDOE log 

for the well that Smith called Clark No. 2 (13N/20E-31L01, 

1,026-ft deep) reported the depth to water as 30 ft and the 

water level in 1897 was more than 100 ft above land surface. 

This indicates that there have been large declines in water 

levels in the lower part of the consolidated unit within the 

upper Moxee subbasin. A few of these early wells are still 

reported to be flowing, but they are the more downgradient 

wells.

Total irrigation pumpage (the largest use) from the basinfill deposits in 2001 was about 68,000 acre-ft (94 ft3/s). A 

map of irrigation wells completed in these deposits (fig. 29) 

indicates they are widely distributed in Yakima and Benton 

Counties with only a few in Kittitas County. Predevelopment 

recharge in the structural basins in Yakima and Benton 

Counties was estimated to be generally less than 3 in/yr, with 

most of the basins receiving less than 0.5 in/yr of recharge; 

the estimate of total mean annual predevelopment recharge in 

these structural basins was about 63 ft3/s. However, currentcondition recharge was estimated to be on the order of 20 in/yr 

in the surface-water irrigated areas that overlie most of the 

deposits in the structural basins (fig. 16). The predevelopment 

recharge would not have been sufficient to meet about a third 

of the historical 2001 pumpage demand without changes in 

either storage and (or) groundwater discharge.

Groundwater levels in the basin-fill deposits generally 

are stable, indicating that the current-condition recharge is 

sufficient to prevent storage changes. However, part of the 

pumpage demand is met by capture of some of the currentcondition recharge, which suggests a reduction in groundwater 

discharge. For example, in the Ahtanum subbasin, Vaccaro 

and Olsen (2007a) estimated mean annual predevelopment 

and current-condition recharge to be 2.7 in. (31 ft3/s) and 

11.6 in. (134 ft3/s), respectively. Irrigation pumpage from 

the basin-fill deposits in this subbasin was estimated to be 

about 20,374 acre-ft (28 ft3/s) in 2001 (about 58 percent of 

the total irrigation pumpage in the subbasin in 2001), and 

other basin-fill pumpage accounts for about 6,320 acre-ft 

(8.7 ft3/s). Pumpage was thus slightly greater (5.7 ft3/s) 

than predevelopment recharge, and adjustments would have 

occurred in the basin-fill flow system (such as decreased 

storage) under existing pumpage and predevelopment recharge 

quantities. Thus, pumpage demand is being partly met by 

the increased recharge under current conditions because no 

changes in storage have occurred. Part of the demand appears 

to be met by decreasing groundwater discharge to streams, as 

evidenced by records of the flow of Ahtanum Creek at Union 

Gap (USGS stream-gaging station 12502500). This station 

has a statistically significant (significance level of 0.003) 

downward trend (slope of -1.2 ft3/s per year) in discharge 

during the August–November period for calendar years 

1962–2002. This trend is not related to climate because the 

rivers without human impacts, such as the American River and 

the Teanaway River below the Forks, do not show this trend. 

This suggests that the pumpage demand that is partly met by 

additional recharge is decreasing the amount of groundwater 

discharge to Ahtanum Creek during its baseflow period.

Most of the downward trends in groundwater levels in 

the Yakima River basin are in the CRBG units. Maps showing 

the generalized trends in water levels (location and magnitude 

of declines) in these units indicate that declines have occurred 

in distinct areas (figs. 30–32). Declines greater than 20 ft 

have the largest areal extent for the Saddle Mountains, about 

177 mi2—about 8 percent of the unit (fig. 30). Assuming 

declines of 21 to 42 ft over this area based on the distribution 

of declines and a storage coefficient of 0.04, the loss in 

groundwater storage due to the water-level declines in 

this unit is conservatively estimated to be from 24,000 to 

48,000 acre-ft. The largest area of decline is on the south flank 

of Rattlesnake Hills, followed by that in the Moxee subbasin. 

Other declines also have occurred in the west-northwest part 

of the Toppenish basin, and near Red Mountain and Richland 

in the Benton basin. The largest declines (greater than 150 ft) 

have principally occurred in parts of the Rattlesnake Hills, 

Moxee, and Cold Creek areas. Declines greater than 20 ft 

also have occurred in the Wanapum (fig. 31) but their areal 

extent (83 mi2—about 2 percent of the unit) is not as large 

as those in the Saddle Mountains; probable declines of more 

than 20 ft have occurred in an additional area of about 74 mi2. 
72 Hydrogeologic Framework of the Yakima River Basin Aquifer System, Washington

Figure 29. Location of irrigation wells completed in the basin-fill deposits, Yakima River basin aquifer system, Washington.

wa19-0148_fig29-Irr wells basin fill 

KITTITAS COUNTY

YAKIMA COUNTY

COUNTY

BENTON COUNTY

KLICKITAT

COUNTY

YAKIMA

Cle Elum

Parker

Wapato

Ellensburg

Umtanum

Kittitas

Thrall

Toppenish

Union Moxee City Gap

Yakima

Selah

Naches

Sunnyside

Richland

Kiona Kennewick Prosser

Grandview

Mabton

Satus

Zillah

Granger

Roza

Easton

Teanaway

Tieton Rimrock

121°

47°

47°

30'

46° 

121°30' 120°30' 120° 119°30'

46°

30'

0 5 10 20 30 MILES

0 5 10 20 30 KILOMETERS

Structural basins

Irrigation districts

Basin model boundary 

Irrigation wells 

EXPLANATION

T.

24

N.

T.

22

N.

T.

20

N.

T.

18

N.

T.

16

N.

T.

14

N.

T.

12

N.

T.

10

N.

T.

8

N.

T.

6

N.

R.10E. R.12E. R.14E. R.16E. R.18E. R.20E. R.22E. R.24E. R.26E. R.28E.

The areas in which water-level declines have occurred are 

more widespread in the Wanapum (in the Toppenish basin, the 

Ahtanum and Moxee subbasins, the Selah basin, and in the 

Black Rock, Dry Creek, and Cold Creek valleys) than in the 

Saddle Mountains, and areas of water-level decline greater 

than 75 ft are larger in the Wanapum. Water-level declines in 

the Grande Ronde are limited to the western Toppenish basin 

and the Ahtanum subbasin, with two small areas of decline in 

the Moxee and Black Rock valleys (fig. 32). Declines of more 

than 20 ft occur in the Grande Ronde over only about 29 mi2, 

less than one-half percent of the areal extent of the unit.

The areas categorized as having water levels that are 

stable or showing only small declines generally are consistent 

with areas of surface-water irrigation, basin-fill deposits, 
Water-Level Trends 73

small quantities of groundwater pumpage, adequate quantities 

of recharge, and (or) low population density; basin-fill units 

with stable water levels also overlie the area of the Saddle 

Mountains and Wanapum on Rattlesnake Hills in which 

water levels declined. The surface-water irrigated areas are 

associated with high recharge values and the low population 

density areas have widely ranging recharge values. The areas 

with moderate declines generally do not lie within most 

surface-water irrigation districts (or if they do, the areas are in 

deeply buried units), have either medium to large population 

density and (or) a reasonable amount of croplands irrigated 

with groundwater. Areas with large declines in water levels 

are in locations similar to those with moderate declines, 

but are closely associated with small rates of groundwater 

recharge, deeply buried units, and large quantities of pumpage 

for irrigation. Lastly, the areas with very large declines are 

generally associated with pumpage from units receiving 

small rates of recharge and (or) large quantities of pumpage 

from more deeply buried units. For the latter case, the units 

may outcrop in an area with small rates of recharge or the 

unit may receive water only from overlying or underlying 

hydrogeologic units (such as the Grande Ronde in the Moxee 

subbasin and Black Rock valley). For the areas of moderate 

to very large water-level declines, the quantity of recharge is 

important. For example, as described previously, mean annual 

recharge for current conditions was estimated to be less than 

2 in. (about 86 ft3/s) over about 2,553 mi2, and during 2000, 

about 30 percent of the groundwater pumpage (about 130 ft3/s) 

was estimated to occur in this area of less than 2 in/yr of 

recharge. Thus, pumpage is much larger than the recharge in 

this drier area.

The largest exception to the general relations described 

above occurs on the south slope of Rattlesnake Hills in a 

surface-water irrigated area. Moderate to very large declines 

in water levels have occurred in the Saddle Mountains and 

Wanapum in this area. The generally fine-grained surficial 

deposits (Touchet Beds and loess), the slope of the land 

surface, drains, and the presence of fine-grained layers in Unit 

3 (the upper Ellensburg Formation is as much as 600 ft thick) 

probably act together to limit deeper downward movement 

of excess surface water (especially through parts of Unit 3). 

As a result, recharge to the Saddle Mountains and Wanapum 

units is limited (mean annual recharge in their outcrop areas 

or where they are overlain by a thin veneer of sediments 

along Rattlesnake Hills is generally less than 0.5 in.). Locally, 

pumpage exceeds the sum of (1) recharge, (2) lateral inflow 

from the upgradient extent of the units, and (3) natural and 

induced vertical leakage from either Unit 3 to the Saddle 

Mountains or from the Saddle Mountains to the Wanapum. 

These factors do not apply to pumpage by wells tapping the 

basin-fill deposits on Rattlesnake Hills, as demonstrated by the 

fact that no water-level declines greater than 20 ft have been 

documented. In this area of naturally small recharge, pumpage 

demand is likely met by additional recharge from surfacewater irrigation. Similar situations occur in or near other 

surface-water irrigation areas in Yakima County for pumpage 

by wells tapping basin-fill deposits, and in Benton County for 

both basin-fill and Saddle Mountains wells.

The factors that influence the degree to which water 

levels are affected by pumping vary spatially and they exert a 

wide range of controls on the groundwater flow system. These 

factors include (1) hydraulic characteristics of the aquifer 

materials, (2) depth in flow system from which withdrawals 

are made, (3) extent and location of outcrop area—including 

the dip and exposure of interflow zones for the CRBG 

units, (4) structural controls, (5) rate of natural recharge 

and of recharge from surface-water delivery and irrigation 

application, and (6) quantity of pumpage. Of these factors, the 

latter two—rates of recharge and amount of water pumped—

probably exert the most control on groundwater levels. 

Estimated total pumpage (fig. 23) and recharge (fig. 33), 

accumulated over the base period of 1960–2001, were about 

33,000 and 291,000 ft3/s, respectively. Where pumping occurs, 

however, the difference between recharge and pumpage 

(fig. 34) indicates that pumpage was much greater than 

recharge in a few areas, and in other areas, recharge was much 

greater than pumpage. The latter case is generally true in the 

structural basins (where surface water is used for irrigation), 

in the wetter parts of the basin, and (or) in areas of low 

population density. Where pumpage is greater than recharge 

and the upgradient source area is small, such as in the upper 

Moxee subbasin and Cold Creek drainage, downward trends 

in groundwater levels are noted (figs. 30–32). Thus, pumpage 

declines may continue in some areas where pumpage is either 

greater than recharge or is only slightly less than recharge and 

the upgradient source area is small. In some areas there appear 

to be large upgradient recharge areas (such as the western 

part of the Toppenish basin), yet water levels are declining. 

Thus, recharge in the upgradient areas cannot meet the 

groundwater withdrawals —likely due to the depth of the 

withdrawals, possible further isolation from overlying, tighter 

basalt flows or fine-grained interbeds, and local discharge 

of recharge in the dissected uplands. In contrast, where 

pumpage is much less than recharge, groundwater levels were 

categorized as stable, such as in the basin-fill deposits in the 

structural basins. Therefore, total cumulative recharge may 

be an order of magnitude larger than cumulative pumpage; 

nonetheless, the spatial distribution of both water-budget 

components is important for determining the effects of 

pumpage on the flow system. Indeed, the spatial distribution 

of recharge is important because mean annual recharge in the 

Saddle Mountains, Wanapum, and Grande Ronde outcrop 

areas ranges widely—1.37, 1.47, and 7.69 in., respectively. 
74 Hydrogeologic Framework of the Yakima River Basin Aquifer System, Washington

wa19_0148_fig30-SM GW trends

KITTITAS COUNTY 

YAKIMA COUNTY 

COUNTY 

BENTON COUNTY

KLICKITAT

COUNTY

YAKIMA

Cle Elum

Parker

Wapato

Ellensburg

Umtanum

Kittitas

Thrall

Toppenish

Moxee City Union Gap

Yakima

Selah

Naches

Sunnyside Richland

Kiona

Kennewick Prosser

Grandview

Mabton

Satus

Zillah

Granger

Roza

Easton

Teanaway

Tieton Rimrock

121°

47°

47°

30'

46° 

121°30' 120°30' 120° 119°30'

46°

30'

0 5 10 20 30 MILES

0 5 10 20 30 KILOMETERS

EXPLANATION

-21 to -75

Saddle Mountains unit

Trends in groundwater levels, in feet 

Irrigation districts

Rise

-76 to -150

Greater than -150

Groundwater levels stable (less than 21 feet

 of decline) unless otherwise noted

WASHINGTON

Extended

study area

 COLUMBIA

 RIVER

T.

24

N.

T.

22

N.

T.

20

N.

T.

18

N.

T.

16

N.

T.

14

N.

T.

12

N.

T.

10

N.

T.

8

N.

T.

6

N.

R.10E. R.12E. R.14E. R.16E. R.18E. R.20E. R.22E. R.24E. R.26E. R.28E.

Figure 30. Generalized trends in groundwater levels, Saddle Mountains unit, Yakima River basin aquifer system, Washington.
Water-Level Trends 75

Figure 31. Generalized trends in groundwater levels, Wanapum unit, Yakima River basin aquifer system, Washington.

wa19_0148_fig31-WANA GW trends

KITTITAS COUNTY 

YAKIMA COUNTY 

COUNTY 

BENTON COUNTY

KLICKITAT

COUNTY

YAKIMA

Cle Elum

Parker

Wapato

Ellensburg

Umtanum

Kittitas

Thrall

Toppenish

Moxee City Union Gap

Yakima

Selah

Naches

Sunnyside Richland

Kiona

Kennewick Prosser

Grandview

Mabton

Satus

Zillah

Granger

Roza

Easton

Teanaway

Tieton Rimrock

121°

47°

47°

30'

46°

121°30' 120°30' 120° 119°30'

46°

30'

0 5 10 20 30 MILES

0 5 10 20 30 KILOMETERS

EXPLANATION

-21 to -75

Wanapum unit

Trends in groundwater levels, in feet 

Irrigation districts

Rise

-76 to -150

Greater than -150

Groundwater levels stable (less than 21 feet

 of decline) unless otherwise noted

Probable greater than 20 feet of decline

WASHINGTON

Extended

study area

 COLUMBIA

 RIVER

T.

24

N.

T.

22

N.

T.

20

N.

T.

18

N.

T.

16

N.

T.

14

N.

T.

12

N.

T.

10

N.

T.

8

N.

T.

6

N.

R.10E. R.12E. R.14E. R.16E. R.18E. R.20E. R.22E. R.24E. R.26E. R.28E.
76 Hydrogeologic Framework of the Yakima River Basin Aquifer System, Washington

wa19_0148_fig32-GR GW trends

EXPLANATION

-21 to -75

Grande Ronde unit

Trends in groundwater levels, in feet 

Irrigation districts

-76 to -150

Greater than -150

Groundwater levels stable (less than 21 feet

 of decline) unless otherwise noted

KITTITAS COUNTY 

YAKIMA COUNTY 

COUNTY 

BENTON COUNTY

KLICKITAT

COUNTY

YAKIMA

Cle Elum

Parker

Wapato

Ellensburg

Umtanum

Kittitas

Thrall

Toppenish

Moxee City Union Gap

Yakima

Selah

Naches

Sunnyside Richland

Kiona

Kennewick Prosser

Grandview

Mabton

Satus

Zillah

Granger

Roza

Easton

Teanaway

Tieton Rimrock

121°

47°

47°

30'

46°

121°30' 120°30' 120° 119°30'

46°

30'

0 5 10 20 30 MILES

0 5 10 20 30 KILOMETERS

WASHINGTON

Extended

study area

 COLUMBIA

 RIVER

T.

24

N.

T.

22

N.

T.

20

N.

T.

18

N.

T.

16

N.

T.

14

N.

T.

12

N.

T.

10

N.

T.

8

N.

T.

6

N.

R.10E. R.12E. R.14E. R.16E. R.18E. R.20E. R.22E. R.24E. R.26E. R.28E.

Figure 32. Generalized trends in groundwater levels, Grande Ronde unit, Yakima River basin aquifer system, Washington.
Water-Level Trends 77

Figure 33. Spatial distribution of cumulative groundwater recharge for 1960–2001, Yakima River basin aquifer system, 

Washington.

wa19_0148_fig33-Cumulative Recharge

KITTITAS COUNTY 

YAKIMA COUNTY 

COUNTY 

BENTON COUNTY

KLICKITAT

COUNTY

YAKIMA

Cle Elum

Parker

Wapato

Ellensburg

Umtanum

Kittitas

Thrall

Toppenish

Moxee City Union Gap

Yakima

Selah

Naches

Sunnyside Richland

Kiona

Kennewick Prosser

Grandview

Mabton

Satus

Zillah

Granger

Roza

Easton

Teanaway

Tieton Rimrock

121°

47°

47°

30'

46° 

121°30' 120°30' 120° 119°30'

46°

30'

0 5 10 20 30 40 MILES

0 5 10 20 30 40 KILOMETERS

EXPLANATION

0 to 12

145 to 168

Greater than 168

Cumulative recharge, in feet 

85 to 144

61 to 84

13 to 36

27 to 60

Yakima

River

Basin

WASHINGTON

 COLUMBIA

 RIVER

T.

24

N.

T.

22

N.

T.

20

N.

T.

18

N.

T.

16

N.

T.

14

N.

T.

12

N.

T.

10

N.

T.

8

N.

T.

6

N.

R.10E. R.12E. R.14E. R.16E. R.18E. R.20E. R.22E. R.24E. R.26E. R.28E.
78 Hydrogeologic Framework of the Yakima River Basin Aquifer System, Washington

wa19-0148_YakimaGW_Fig.34-DIFF_Pumpage/Recharge

-52.1 to -10.0

-9.9 to 0

0.1 to 2.0

2.1 to 4.0

4.1 to 7.0

7.1 to 20.0

Greater than 20

EXPLANATION

Difference between groundwater recharge

 and pumpage, in feet, accumulated from

 1960-2001, for areas with pumpage.

 Block size is one-quarter township

Pumpage greater than recharge

Recharge greater than pumpage

3020100 40 KILOMETERS

0 10 20 30 40 MILES

Bumping

Lake

S Fk

N Fk

Cle Elum River

Bumping River

Ahtanum Creek

Tieton River Wenas Creek

North Fork

Dry Creek

Creek

Toppenish

RIVER

YAKIMA

Satus

Creek

Cle

Elum

Lake

Rimrock

Lake

Kachess Lake

Keechelus Lake

Lake

Wallula

Teanaway River

Umtanum Creek

Little Naches River

Cowiche Creek

Cowiche Creek

River

Naches

RIVER

YAKIMA

RIVER

YAKIMA

Bumping

Lake

S Fk

N Fk

Cle Elum River

Bumping River

Ahtanum Creek

Tieton River Wenas Creek

North Fork

Dry Creek

Creek

Toppenish

RIVER

YAKIMA

Satus

Creek

Cle

Elum

Lake

Rimrock

Lake

Kachess Lake

Keechelus Lake

Lake

Wallula

Teanaway River

Umtanum Creek

Little Naches River

Cowiche Creek

Cowiche Creek

River

Naches

RIVER

YAKIMA

RIVER

YAKIMA

Sunnyside Richland

Yakima

Ellensburg

T.

25

N.

T.

23

N.

T.

21

N.

T.

19

N.

T.

17

N.

T.

15

N.

T.

13

N.

T.

11

N.

T.

9

N.

T.

7

N.

T.

5

N.

R.11E. R.13E. R.15E. R.17E. R.19E. R.21E. R.23E. R.25E. R.27E. R.29E.

121°30' 121° 120°30' 120° 119°30'

47°

46°30'

47°30'

46°

Figure 34. Spatial distribution of the difference between groundwater recharge and pumpage acummulated for 1960–2001 

for areas with pumpage, Yakima River basin aquifer system, Washington.
Water Budget for the Yakima River Basin 79

Although data on recharge and pumpage are important 

for understanding downward trends in water levels, the 

magnitude of the declines also is controlled by geologic 

structure, topography, and the extent and hydraulic 

characteristics of a given hydrogeologic unit. For example, 

geologic structure can compartmentalize the flow system and 

thus, limit the upgradient groundwater source area. Similarly, 

topography can affect the flow system and also limit the 

source area. The extent and hydraulic characteristics of a unit 

act in concert to control water-level changes. For example, 

water levels in a buried unit have less potential to be stable 

under pumping stresses unless the flow rate into the unit is 

large. Flow into a buried unit can be large in areas of regional 

groundwater discharge. For example, the Saddle Mountains 

unit below the Yakima River would receive not only lateral 

inflow but also upward flow from the Wanapum. Where the 

rate of replenishment is small, such as in parts of the Grande 

Ronde and Unit 3 in the Roslyn basin, water-level declines 

occur due to pumping; where the rate of replenishment is 

large, such as in Unit 2 in the Toppenish basin and most of 

Unit 3 in the Ahtanum subbasin, water levels tend to be stable. 

The more permeable hydrogeologic units, such as the alluvial 

units, can be readily recharged and replenished, whereas 

the less permeable units, such as the Mesozoic unit, are less 

readily recharged, and lateral flow (replenishment) into a 

pumping area is limited. 

Water Budget for the 

Yakima River Basin

A generalized mean annual water budget for the Yakima 

River basin was estimated based on information developed 

during this study. The budget provides an overview of 

the magnitude of the various components and includes 

information important for understanding the framework 

of the groundwater system in the basin. The water-budget 

components are: precipitation, streamflow, evapotranspiration, 

potential recharge, groundwater pumpage, reservoir storage, 

surface-water diversions, groundwater storage, and changes 

in storage. The components are briefly described in table 6. 

These components are, where applicable, shown for both 

predevelopment (no human activities) and current conditions, 

and are referenced to the base period, water years 1960–2001. 

Values presented also are generally rounded values. A 

more detailed water budget for the aquifer system will be 

estimated on the basis of the regional groundwater flow model 

simulations.

The mean annual precipitation over the basin is about 

27 in. (about 12,300 ft3/s or 8.9 million acre-ft). The mean 

annual precipitation is referenced to the climate normal of 

1971–2000, which, based on mean annual streamflow, would 

be about 4 percent larger than the 1960–2001 base period. This 

change is similar to the previously described percent decrease 

in mean annual recharge for the base period in comparison to 

the 1950–2001 period. Thus, referenced to the base period, 

mean annual precipitation is about 26 in. (11,800 ft3/s or 

8.6 million acre-ft), and is applicable to both predevelopment 

and current conditions.

 The Yakima River basin produces a mean annual 

unregulated streamflow (adjusted for regulation and without 

diversions or returns, and referenced to the base period) of 

about 5,300 ft3/s (about 4.1 million acre-ft) and a regulated 

streamflow, referenced to the base period, of about 3,500 ft3/s 

(about 2.5 million acre-ft). The regulated streamflow is 

based on discharge records collected at the USGS streamgaging station for the Yakima River at Kiona (station number 

12510500) located in the lower part of the basin, which has a 

long-term mean annual discharge of about 3,500 ft3/s for its 

period of record (1934–2007).

The difference between the mean annual precipitation 

and mean annual unregulated streamflow is about 

7,000 ft3/s (5.1 million acre-ft). Assuming no change in 

groundwater storage over the base period, this difference 

indicates that about 57 percent of the precipitation is lost to 

evapotranspiration under natural conditions. The difference 

between the mean annual precipitation and mean annual 

regulated streamflow is about 8,300 ft3/s (6.1 million 

acre-ft), indicating that about 70 percent of the precipitation 

is currently being lost to evapotranspiration. Thus, human 

activities, in particular irrigated agriculture, have increased 

evapotranspiration by about 1,300 ft3/s (0.9 million acre-ft), 

which is about equivalent to the total storage capacity in the 

basin.

Table 6. Generalized mean annual water budget for the Yakima 

River basin, Washington.

[Predevelopment conditions assumes 1960–2001 climate without human 

activities. Current conditions represent a composite 1995–2004 land use/land 

cover; mean annual values referenced to water years 1960–2001. All values in 

million acre-feet, rounded]

Water budget 

component

Predevelopment 

conditions

Current 

conditions

Precipitation 8.6 8.6

Streamflow 4.1 2.5

Evapotranspiration 5.1 6.1

Recharge1 3.8 5.0

Pumpage .0 .24

Reservoir storage .0 1.1

Diversions2 .0 3.1

1

For predevelopment conditions, a large part of estimated recharge 

becomes streamflow; for current conditions, part of the recharge also becomes 

evapotranspiration.

2

Does not include power generation diversions.
80 Hydrogeologic Framework of the Yakima River Basin Aquifer System, Washington

The potential mean annual recharge for the base period 

was about 15.2 in. or 6,860 ft3/s (4.97 million acre-ft). 

Predevelopment mean annual recharge is about 11.5 in. or 

5,250 ft3/s (3.8 million acre-ft). The predevelopment estimate 

is also referenced to the base period, which is about 3 percent 

less than the estimate for the 1950–2003 recharge-estimation 

period. Most of the recharge supports local streamflow along 

short flow paths. The estimated mean annual groundwater 

pumpage for the base period was about 244,000 acre-ft 

(340 ft3/s).

Six dams were constructed as part of Reclamation’s 

Yakima Project: Bumping Dam in 1910, Kachess Dam in 

1912, Clear Creek Dam in 1914, Keechelus Dam in 1917, 

Tieton Dam (Rimrock Lake) in 1925, and Cle Elum Dam in 

1933. The reservoirs have a total storage capacity of about 

1.07 million acre-ft, of which about 78 percent is in the upper 

arm of the Yakima River and 22 percent is in the Naches River 

arm.

Excluding diversions for power generation, mean annual 

discharge (water years 1960–2001) for the 65 diversions was 

about 3,910 ft3/s (2.8 million acre-ft). The total for the other 

78 points of withdrawals was 474 ft3/s (0.3 million acre-ft). 

Together, the non-power quantities total about 4,384 ft3/s or 

3.1 million acre-ft. 

Summary and Conclusions

The Yakima River basin aquifer system underlies about 

6,200 mi2 in south-central Washington. The study-area 

boundary was extended eastward to the Columbia River 

(incorporating an additional 700 mi2) to provide a more 

definitive hydrologic boundary for construction of a regional 

groundwater flow model.

The aquifers in the Yakima River basin consist of 

sedimentary deposits in six structural basins, volcanic rocks 

of the Columbia River Basalt Group (CRBG), and generally 

older bedrock. The basin-fill deposits were divided into 19 

hydrogeologic units, the CRBG was divided into three units 

separated by two interbed units, and the bedrock was divided 

into four units (based on geologic age) and several subunits. 

The thickness of the basin-fill units and the depth to the top 

of each unit and interbed of the CRBG were mapped. Only 

the surficial extent of the bedrock units was mapped due to 

insufficient data. 

The lithology of the basin-fill units ranges from 

coarse-grained alluvial-valley deposits to fine-grained claydominated deposits. In three of the structural basins, an 

alluvial, unconsolidated, and a consolidated unit were mapped, 

although five units were mapped in the Toppenish basin. 

Two units, one unconsolidated and the other consolidated, 

were mapped in the Benton basin; in the Eastern Benton 

basin, the unconsolidated unit was further divided into six 

subunits which occur together only in this part of the study 

area. Average mapped thickness of the different units ranged 

from 10 to 600 ft and the median thickness ranged from 10 to 

450 ft.

The CRBG units consist of three formations and their 

interbedded sediments. The formations were called units to 

account for the sediments and they are named, from oldest 

to youngest, the Grande Ronde, Saddle Mountains, and 

Wanapum units. The Grande Ronde unit is the most extensive 

and the Saddle Mountains the least extensive. Average 

mapped thicknesses of the Saddle Mountains and Wanapum 

units were 550 and 600 ft, respectively. The thickness of the 

Grande Ronde unit was not mapped due to insufficient data. 

The Mabton Interbed lies between the Saddle Mountains and 

Wanapum units, and the Vantage Interbed lies between the 

Wanapum and Grande Ronde units. The Mabton Interbed 

averages 70 ft in thickness and the Vantage Interbed averages 

30 ft.

The four bedrock units, consisting of the Paleozoic, 

the Mesozoic, the Tertiary, and the Quaternary bedrock, 

underlie the western part of the basin. The combined areas of 

these units where they abut the CRBG are about 1,520 mi2. 

The Tertiary unit has the largest extent (1,300 mi2) and 

the Paleozoic unit the smallest (2 mi2). The Paleozoic unit 

consists of metamorphic rocks and the Mesozoic unit has 

three subdivisions consisting of metamorphic, volcanic, 

and plutonic rocks. The Tertiary unit has three subdivisions 

consisting of sediments, and volcanic and plutonic rocks. The 

Quaternary bedrock unit consists principally of volcanics but 

in a few small areas it consists of sediments.

Lateral hydraulic conductivity (Kh) of the hydrogeologic 

units ranges widely, indicating the heterogeneity of the 

geologic materials making up the aquifer system. Average 

or effective Kh values of the water-producing zones of the 

basin-fill units are on the order of 1 to 800 ft/d and are about 

1 to 5 ft/d for the CRBG units. Effective Kh for the different 

rock types of the Paleozoic, Mesozoic, and Tertiary bedrock 

units appear to be about 0.0001 to 3 ft/d. The more permeable 

Quaternary bedrock unit may have Kh values that range 

from 1 to 7,000 ft/d. Based on specific-capacity data, mean 

and median values for basin-fill units were 182 and 6 ft/d, 

respectively. The specific-capacity derived mean and median 

values for CRBG units were 182 and 3 ft/d, respectively, and 

for the bedrock units they were 13 and 3 ft/d, respectively. 

Vertical hydraulic conductivity (Kv) of the units is largely 

unknown. Kv values have been estimated to range from about 

0.009 to 2 ft/d for the basin-fill units; values for the clay-toshale parts of these units may be as small as 10-10 to 10-7 ft/d. 

Reported Kv values for the CRBG units range from 4×10-7 to 

4 ft/d.

Variations in the concentrations of geochemical solutes 

and the concentrations and ratios of the isotopes of hydrogen, 

oxygen, and carbon in groundwater provide information on 

the hydrogeologic framework of the groundwater system in 

the Yakima basin. The concentrations of dissolved constituents 

in groundwater vary in response to the interactions of 

groundwater with the aquifer matrix material. Dissolved 

solutes in basaltic groundwater of the CRBG are derived 

principally from the dissolution of basaltic glass and to a 

lesser extent plagioclase feldspar. Ratios of the stable isotopes 

of hydrogen and oxygen (deuterium and oxygen-18) indicated 
Acknowledgments 81

dispersed sources of groundwater recharge to the CRBG and 

Ellensburg aquifers. Carbon and tritium isotope data and the 

concentrations of dissolved constituents indicate a complex 

groundwater flow system with multiple contributing zones 

to groundwater wells and relative groundwater residence 

time on the order of a few tens to many thousands of years. 

The concentrations of dissolved methane were larger than 

could be attributed to atmospheric sources in more than 

80 percent of wells with measured methane concentrations. 

Concentrations of methane as large as 50 mg/L were measured 

even though dissolved concentrations of noble gases argon 

and neon showed substantial alteration from atmospheric 

concentrations, likely due to partial stripping of the gases 

during sampling. The stable carbon isotopic composition 

(δ13Cmethane; 13C/12C) of dissolved methane varied from 

-32.7 to -53.0 ‰—which is indicative of a thermogenic 

source for the methane. Most of the detections of methane 

were in samples from irrigation and municipal wells at 

locations several miles distant from mapped structural 

fault features, suggesting the upward vertical movement of 

thermogenic methane from the underlying bedrock may be 

more widespread than assumed or the presence of unmapped 

(buried) fault structures. The spatial distribution of methane 

suggests both diffuse and point sources (faults). 

Potential mean annual recharge for current conditions 

for water years 1950–2003 was estimated to be about 15.6 in. 

or 7,149 ft3/s (5.2 million acre-ft) and if there had been no 

human activities (predevelopment conditions) during that 

period, estimated recharge would have been about 11.9 in. 

or 5,450 ft3/s (3.9 million acre-ft). Recharge amounts range 

widely with location within the basin. Estimated mean annual 

recharge ranges from virtually zero in the dry parts of the 

lower basin to more than 100 in. in the humid uplands that 

receive more than 120 in/yr of precipitation. Within the 

Yakima River basin, mean annual recharge for the base period 

of interest (water years 1960–2001) was about 15.2 in. or 

6,860 ft3/s (4.97 million acre-ft). These values account for the 

refinements in selected irrigation districts for the years with 

prorating when junior surface-water users do not obtain their 

full entitlement, and for the different base period (1960–2001 

in contrast to 1950–2003). For the extended study area, 

mean annual recharge was estimated to be about 13.6 in. or 

6,950 ft3/s.

Groundwater in the study area occurs under perched, 

unconfined, semiconfined, and confined conditions. The water 

moves from topographic highs in the uplands to topographic 

low areas along the streams. The flow system in the basin-fill 

units is compartmentalized due to topography and geologic 

structure. The system also is compartmentalized for the 

CRBG units but not to as large an extent as the basin-fill units. 

Regional groundwater flow discharges to surface drainage 

features in the lowlands in the structural basins and to the 

Columbia River. The gradient of the water table ranges from 

about 7 feet per mile to more than 400 feet per mile, with the 

more “gentle” gradients in the topographically smooth parts of 

the structural basins. Typically, hydraulic gradients are similar 

to topographic gradients. The lateral hydraulic gradient in the 

CRBG units also is highly variable and ranges from about 3 

to 14 feet per mile in the flatter parts of the structural basins 

to as much as 800 feet per mile in areas of steep terrain. In 

the CRBG units, the hydraulic gradient generally is within 

5 degrees of the topographic gradient.

There are nearly 2,874 groundwater rights in the 

basin, with an annual total of 530,000 acre-ft (730 ft3/s). 

Allowable acreage of groundwater irrigation rights is about 

130,000 acres. A total of 312,284 acre-ft of water (about 

430 ft3/s) was estimated to have been pumped in 2000 for 

multiple uses, about 60 percent of which was for irrigation. 

Standby/reserve pumpage was estimated to have ranged from 

about 9,200 acre-ft in 1988 to 52,100 acre-ft in 1994 and 

2001, and total standby/reserve pumpage for the 8 prorating 

years through 2001 was about 250,350 acre-ft. Surface-water 

diversions (minus power returns) are about 4,383 ft3/s, of 

which about 66 percent was delivered for irrigation.

Excluding the initial water-level rises due to surfacewater irrigation that started in the late 1800s, long-term 

measurements of the levels indicate they have been stable or 

have declined less than 20 ft in most of the aquifer system. 

Declines from 21 to 300 ft have occurred in some areas due 

to pumpage. The largest declines have been in the CRBG 

units. The pumpage from the basin-fill units, from which 

about 50 percent of the pumpage occurs, appears to have 

caused water-level declines in only two small areas, but the 

withdrawals may be reducing groundwater discharge.

For current conditions, the largest mean annual waterbudget component was precipitation (8.6 million acre-ft), 

followed by evapotranspiration (6.1 million acre-ft). Potential 

groundwater recharge was estimated to be 5.0 million acre-ft, 

and streamflow was about one-half of the recharge (2.5 million 

acre-ft). Diversions amounted to about 3.1 million acre-ft, 

which is about three times larger than the reservoir capacity 

in the basin (1.1 million acre-ft). Pumpage was the smallest 

water budget component at 0.25 million acre-ft.

Acknowledgments

The authors wish to thank the Bureau of Reclamation, 

Bureau of Indian Affairs, Washington State Department of 

Ecology, the Yakima Nation, and groups such as conservation 

and irrigation districts that provided valuable support and 

access to their records during this study. We especially wish 

to thank the numerous well owners in the basin who provided 

access to their wells to gather information that was an 

essential part of this study. Tyler Coplen, National Research 

Program, Water Resources Discipline, U.S. Geological Survey 

is thanked for providing the numerous stable isotope data for 

surface-water sites.
82 Hydrogeologic Framework of the Yakima River Basin Aquifer System, Washington

Selected References

Ames, L.L., 1980, Hanford basalt flow mineralogy: Richland, 

Wash., Pacific Northwest Laboratory, PNL-2847, 447 p.

Bauer, H.H., and Hansen, A.J., 2000, Hydrology of the 

Columbia Plateau aquifer system, Washington, Oregon, 

and Idaho: U.S. Geological Survey Water-Resources 

Investigations Report 96-4106, 61 p., accessed June 8, 

2007, at http://pubs.er.usgs.gov/usgspubs/wri/wri964106

Bauer, H.H., and Vaccaro, J.J., 1987, Documentation of a 

Deep Percolation Model for estimating ground-water 

recharge: U.S. Geological Survey Open-File Report 86-536, 

180 p., accessed March 17, 2009, at http://pubs.er.usgs.gov/

usgspubs/ofr/ofr86536

Bauer, H.H., and Vaccaro, J.J., 1990, Estimates of groundwater recharge to the Columbia Plateau regional 

aquifer system, Washington, Oregon, and Idaho, for 

predevelopment and current land-use conditions: U.S. 

Geological Survey Water-Resources Investigations 

Report 88-4108, 37 p., 2 pls., accessed June 8, 2007, at 

http://pubs.er.usgs.gov/usgspubs/wri/wri884108

Bauer, H.H., Vaccaro, J.J., and Lane, R.C., 1985, Maps 

showing ground-water levels in the Columbia River Basalt 

Group and overlying material, spring 1983, southeastern 

Washington: U.S. Geological Survey Water-Resources 

Investigations Report 84-4360, 4 sheets, accessed June 8, 

2007, at http://pubs.er.usgs.gov/usgspubs/wri/wri844360

Benson, L.V., and Teague, L.S., 1982, Diagenesis of basalts 

from the Pasco basin, Washington—Distribution and 

composition of secondary mineral phases: Journal of 

Sedimentary Petrology, v. 52, no. 2, p. 595-613.

Bentall, Ray, 1963, Methods of determining permeability, 

transmissibility, and drawdown: U.S. Geological Survey 

Water Supply Paper 1536-I, p. 331-341, accessed March 17, 

2009, at http://pubs.er.usgs.gov/usgspubs/wsp/wsp1536I

Berger, D.L., 2000, Water-budget estimates for the 14 

hydrographic areas in the middle Humboldt River basin, 

north-central Nevada: Washington: U.S. Geological Survey 

Water-Resources Investigations Report 00-4168, 55 p.

Bergeron, M.P., Freshly, M.D., Last, G.V., and Mitchell, P.J., 

1986, Development of the Hanford three-dimensional 

ground-water flow model: Richland, Wash., Battelle Pacific 

Northwest Laboratory, draft report, 14 p.

Bolke, E.L., and Skrivan, J.A., 1981, Digital-model 

simulation of the Toppenish alluvial aquifer, Yakima Indian 

Reservation, Washington: U.S. Geological Survey OpenFile Report 81-425, 34 p.

Bolke, E.L., and Vaccaro, J.J., 1981, Digital-model simulation 

of the hydrologic flow system, with emphasis on ground 

water, in the Spokane Valley, Washington and Idaho: U.S. 

Geological Survey Open-File Report 80-1300, 43 p.

Bortleson, G.C., and Cox, S.E., 1986, Occurrence of 

dissolved sodium in ground waters in basalts underlying 

the Columbia Plateau, Washington: U.S. Geological Survey 

Water-Resources Investigations Report 85-4005, 24 p., 6 

sheets, accessed March 13, 2009, at http://pubs.er.usgs.gov/

usgspubs/wri/wri854005

Bredehoeft, J.D., Neuzil, C.E., and Milly, P.C.D, 1983, 

Regional flow in the Dakota aquifer: A study of the role 

of confining layers: U.S. Geological Survey Water Supply 

Paper 2237, 34 p., accessed June 8, 2009, at http://pubs.

er.usgs.gov/usgspubs/wsp/wsp2237

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.

Brown, Randall, 1979, A review of water-well data from the 

unconfined aquifer in eastern and southern parts of the 

Pasco basin: Richland, Wash., Rockwell International, 

Rockwell Hanford Operations, RHO-BWI-C-56, 63 p., 

11 pl.

Bureau of Reclamation, 1984, Drainage manual: Denver, 

Colo., U.S. Government Printing Office, 286 p.

Bureau of Reclamation, 1999, Yakima River basin water 

enhancement project, Washington, Final programmatic 

environmental impact statement: U.S. Department of 

Interior, Bureau of Reclamation, Pacific Northwest Region, 

Upper Columbia Area Office, Yakima, Wash., 197 p.

Campbell, N.P., 1989, Structural and stratigraphic 

interpretation of rocks under the Yakima fold belt, Columbia 

Basin, based on recent surface mapping and well data, 

in, Reidel, S.P., and Hooper, P.R., eds., Volcanism and 

tectonism in the Columbia River flood-basalt province: 

Boulder, Colo., Geological Society of America, Special 

Paper 239, p. 209-222.

Carnahan, B., Luther, H.A., and Wilkes, J.O., 1969, Applied 

numerical methods: New York, John Wiley and Sons, Inc., 

604 p.

Clark, I.D., and Fritz, Peter, 1997, Environmental isotopes in 

hydrogeology: Boca Raton, Fla., Lewis Publishers, 328 p.

Converse Consultants NW, 1991, Construction and testing 

of Kissell Park well for City of Yakima, Washington: 

Draft report prepared for R.W. Beck and Associates, 

October 1989.
Selected References 83

Cooper, H.H., and Jacob, C.E., 1946, A generalized graphical 

method for evaluating formation constants and summarizing 

well field history: American Geophysics Union 

Transactions, v. 27, p. 526-534.

Coplen, T.B., and Kendall, Carol, 2000, Stable hydrogen 

and oxygen isotope ratios for selected sites of the U.S. 

Geological Survey’s NASQAN and benchmark surfacewater networks: U.S. Geological Survey Open-File Report 

2000-160, 409 p., accessed January 13, 2009, at http://pubs.

er.usgs.gov/usgspubs/ofr/ofr00160

Coplen, T.B., Neiman, P.J., White, A.B., Landwehr, J.M., 

Ralph, F.M., and Dettinger, M.D., 2008, Extreme changes in 

stable hydrogen isotopes and precipitation characteristics in 

a landfalling Pacific storm: Geophysical Research Letters, 

v. 35, L21808, 5 p.

Craig, H., 1961, Isotopic variations in meteoric water: 

Science, v. 133, no. 3465, p. 702

Cuffney, T.F., Meador, M.R., Porter, S.D., and Gurtz, M.E, 

1997, Distribution of fish, benthic invertebrate, and 

algal communities in relation to physical and chemical 

conditions, Yakima River basin, Washington, 1990: U.S. 

Geological Survey Water-Resources Investigations Report 

96-4280, 94 p., accessed January 13, 2009, at http://pubs.

er.usgs.gov/usgspubs/wri/wri964280

Davies-Smith, Ann, Bolke, E.L., and Collins, C.A., 1988, 

Geohydrology and digital simulation of the ground-water 

flow system in the Umatilla Plateau and Horse Heaven 

Hills area, Oregon and Washington: U.S. Geological Survey 

Water-Resources Investigations Report 87-4268, 72 p., 

accessed January 13, 2009, at http://pubs.er.usgs.gov/

usgspubs/wri/wri874268

Didricksen, Kayti, 2004, Appraisal assessment of 

hydrogeology at a potential Black Rock damsite: U.S. 

Bureau of Reclamation, Technical Series No. TS-YSS-6, 

28 p., 2 appendixes.

Dinicola, R.S., 1997, Estimates of recharge from runoff at the 

Hanford Site, Washingtion: U.S. Geological Survey WaterResources Investigations Report 97-4038, 172 p., accessed 

January 13, 2009, at http://pubs.er.usgs.gov/usgspubs/wri/

wri974038

Drost, B.W., Cox, S.E., and Schurr, K.M., 1997, Changes 

in ground-water levels and ground-water budgets, from 

predevelopment to 1986, in parts of the Pasco basin, 

Washington: U.S. Geological Survey Water-Resources 

Investigations Report 96-4086, 172 p., accessed January 13, 

2009, at http://pubs.er.usgs.gov/usgspubs/wri/wri964086

Drost, B.W., Whiteman, K.J., and Gonthier, J.B., 1990, The 

geologic framework of the Columbia Plateau regional 

aquifer system, Washington, Oregon, and Idaho: U.S. 

Geological Survey Water-Resources Investigations Report 

87-4238, 10 p., 10 sheets, accessed January 13, 2009, at 

http://pubs.er.usgs.gov/usgspubs/wri/wri874238

Early, T.O., Spice, G.D., and Mitchell, M.D., 1986, A 

hydrochemical data base for the Hanford site, Washington: 

Richland, Wash., Rockwell Hanford Operations, 

SD-BWIP-DP-061, 186 p.

Eslinger, P.W., 1986, Probability distribution of horizontal 

hydraulic conductivity in Grande Ronde Basalt flow 

interiors: Richland, Wash., Rockwell Hanford Operations, 

Computational Brief No. 550, 3 p.

Ferris, J.G., Knowles, D.B., Brown, R.H., and Stallman, R.W., 

1962, Theory of aquifer tests: U.S. Geological Survey Water 

Supply Paper 1536-E, 174 p., accessed June 8, 2009, at 

http://pubs.er.usgs.gov/usgspubs/wsp/wsp1536E

Fishman, M.J., and Friedman, L.C., eds., 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., 

accessed June 8, 2009, at http://pubs.usgs.gov/twri/twri5-a1/

Flaherty, N.M., 1975, The Yakima basin and its water: 

Pullman, Wash., Washington State University, Water 

Resource Center, 29 p. 

Foxworthy, B.L., 1962, Geology and ground-water resources 

of the Ahatanum Valley, Yakima County, Washington: U.S. 

Geological Survey Water Supply Paper 1598, 100 p., 3 pls., 

accessed June 8, 2007, at http://pubs.er.usgs.gov/usgspubs/

wsp/wsp1598

Freeze, R.A., and Cherry, J.A., 1979, Groundwater: 

Englewood Cliffs, N.J., Prentice-Hall, 604 p.

Frizzell, V.A., Jr., Tabor, R.W., Booth, D.B., Ort, K.M., and 

Waitt, R.B., Jr., 1984, Preliminary geologic map of the 

Snoqualmie Pass 1:100,000 quadrangle, Washington: U.S. 

Geological Survey Open-File Report 84-693, 36 p., 1 sheet, 

scale 1:100,000.

Fuhrer, G.J., McKenzie, S.W., Rinella, J.F., and Skach, K.A., 

1994 Surface-water assessment of the Yakima River basin 

in Washington—Analysis of major and minor elements in 

fine-grained-streambed sediment, 1987, with a section on 

geology, by Gannett, M.W.: U.S. Geological Survey OpenFile Report 93-30, 226 p., accessed January 13, 2009, at 

http://pubs.er.usgs.gov/usgspubs/ofr/ofr9330
84 Hydrogeologic Framework of the Yakima River Basin Aquifer System, Washington

Gannett, M.W., and Lite, K.E., 2004, Simulation of regional 

ground-water flow in the upper Deschutes basin, Oregon: 

U.S. Geological Survey Water-Resources Investigations 

Report 03-4195, 84 p., accessed December 8, 2008, at 

http://pubs.er.usgs.gov/usgspubs/wri/wri034195

Garabedian, S.P, 1986, Application of a parameter-estimation 

technique to modeling the regional aquifer underlying the 

Snake River Plain, Idaho: U.S. Geological Survey Water 

Supply Paper 2278, 60 p., accessed January 13, 2009, at 

http://pubs.er.usgs.gov/usgspubs/wsp/wsp2278

Gat, J.R., 1980, The isotopes of hydrogen and oxygen in 

precipitation, in Fritz, Peter, and Fontes, J.C., eds., Chapter 

1—Handbook of environmental isotope geochemistry: 

Amsterdam, Elsevier Press, p. 21-48.

Gazis, Carey, Taylor, S.A., Hammond, Travis, and Howarth, 

Kathren, 2007, Stable isotopic constraints on surface 

water-groundwater interactions in the Upper Yakima River 

Basin, Washington [abs]: 6th Washington Hydrogeology 

Symposium, May 1-3, 2007, Program, p. 104.

GeoEngineers, 1999, Report of hydrogeological services—

Wellhead protection plan, Ellensburg, Washington: 

GeoEngineers, File no. 6304-001-00-5180, 39 p. (plus 

figures and tables).

Glantz, M.H., 1982, Consequences and responsibilities in 

drought forecasting—The case of Yakima, 1977: Water 

Resources Research, v. 18, no. 1, p. 3-13.

Golder Associates, 2001, Aquifer storage and recovery (ASR) 

pilot test report, Yakima, Washington: Golder Associates, 

File no. 983-1085-001.9000, 36 p., 3 appendixes, (plus 

figures and tables).

Golder Associates, 2002, Naches Basin (WRIA 38) storage 

assessment application of aquifer storage and recovery: 

Golder Associates, File no. 983-1085-002.400, 48 p. (plus 

figures and tables).

Graham, M.J., 1981, Hydrology of the separations area: 

Richland, Wash,, Rockwell International, Rockwell Hanford 

Operations, RHO-ST-42, 104 p.

Gregg, D.O., and Laird, L.B., 1975, A general outline of the 

water resources of the Toppenish Creek basin, Yakama 

Indian Reservation, Washington: U.S. Geological Survey 

Open-File Report 75-19, 37 p.

Gulick, G.W., and Korosec, M.A., 1990, Geologic map of the 

Banks Lake 1:100,000 quadrangle, Washington: Washington 

Division of Geology and Earth Resources, Open File-Report 

90-6, 20 p., 1 sheet, scale 1:100,000.

Hammer, A.A., 1934, Rattlesnake Hills gas field, Benton, 

County, Washington: Bulletin of the American Association 

of Petroleum Geologists, v. 18, no. 7, p. 847-859.

Hansen, A.J., Vaccaro, J.J., and Bauer, H.H., 1994, Groundwater flow simulation of the Columbia Plateau regional 

aquifer system, Washington, Oregon, and Idaho: U.S. 

Geological Survey Water-Resources Investigations Report 

91-4187, 101 p., 15 sheets, accessed December 8, 2008, at 

http://pubs.er.usgs.gov/usgspubs/wri/wri914187

Hearn, P.P, Steinkampf, W.C., Bortleson, G.C., and Drost, 

B.W., 1985, Geochemical controls on dissolved sodium in 

basalt aquifers of the Columbia Plateau, Washington: U.S. 

Geological Survey Water-Resources Investigations Report 

84-4304, 38 p., 1 pl., accessed January 13, 2009, at http://

pubs.er.usgs.gov/usgspubs/wri/wri844304

Heaton, T.H.E., and Vogel, J.C., 1981, ‘Excess air’ in ground 

water: Journal of Hydrology. v. 50, p. 201-216.

Hendry, James, Armstrong, Steve, and Ring, Tom, 1992, 

Application of environmental isotopes to the study of 

ground waters in the Toppenish Creek basin, Washington: in

Jones, M.E., and Laenen, Antonius, eds., Interdisciplinary 

approaches in hydrology and hydrogeology: American 

Institute of Hydrology, p. 107-118. 

Hollyday, E.F., and Hileman, G.E., 1996, Hydrogeologic 

terranes and potential yield of water to wells in the 

valley and ridge physiographic province in the eastern 

and southeastern United States: U.S. Geological Survey 

Professional Paper 1422-C, 30 p., 5 pls., accessed January 

13, 2009, at http://pubs.er.usgs.gov/usgspubs/pp/pp1422C

Hotchkiss, W.R., and Levings, J.F., 1986, Hydrogeology and 

simulation of water flow in strata above Bearpaw Shale and 

equivalents of eastern Montana and northeastern Wyoming: 

U.S. Geological Survey Water-Resources Investigations 

Report 85-4281, 72 p., accessed June 8, 2009, at http://pubs.

er.usgs.gov/usgspubs/wri/wri854281

Hubbert, M.K., 1940, The theory of ground-water motion: 

Journal of Geology, v. 48, no. 8, pt. 1, p. 785-944

Ingebritsen, S.E., Sherrod, D.R., and Mariner, R.H., 1992, 

Rates and patterns of groundwater flow in the Cascade 

Range volcanic arc, and the effect on subsurface 

temperatures: Journal of Geophysical Research, v. 97, 

no. B4, p. 4599-4627.

Jayne, S.O, 1907, Irrigation in the Yakima Valley, Washington: 

U.S. Department of Agriculture, Office of Experiment 

Stations, Bulletin 188, July 3, 1907, 89 p.

Johnson, V.G., Graham, L., and Reidel, S.P., 1993, Methane 

in Columbia River basalt aquifers—Isotopic and 

geohydrologic evidence for a deep coal-bed gas source in 

the Columbia Basin, Washington: American Association of 

Petroleum Geologists Bulletin v. 77, no. 7, p. 1192-1207.
Selected References 85

Jones, M.A., and Vaccaro, J.J., 2008, Extent and depth to the 

top of basalt and interbed hydrogeologic units, Yakima 

River basin aquifer system, Washington: U.S. Geological 

Survey Scientific Investigations Report 2008-5045, 22 p., 

5 pls., accessed April 2, 2008, at http://pubs.er.usgs.gov/

usgspubs/sir/sir20085045

Jones, M.A., Vaccaro, J.J., and Watkins, A.M., 2006, 

Hydrogeologic framework of sedimentary deposits in 

six structural basins, Yakima River basin, Washington: 

U.S. Geological Survey Scientific Investigations 

Report 2006-5116, 24 p., 7 pls., accessed June 8, 2007, at 

http://pubs.water.usgs.gov/sir2006-5116

Kendall, Carol, and Coplen, T.B., 2001, Distribution of 

oxygen-18 and deuterium in river waters across the United 

States: Hydrological Processes, v. 15, p. 1363-1393.

Keys, M.E., Vaccaro, J.J., Jones, M.A., and Julich, R.J., 

2008, Hydrographs showing ground-water level trends for 

selected wells in the Yakima River Basin aquifer system, 

Washington: U.S. Gological Survey Data Series 343, 

accessed April 29, 2008, at http://pubs.usgs.gov/ds/343

Khaleel, R., and Freeman, E.J., 1995, Variability and scaling 

of hydraulic properties for 200 area soils, Hanford Site: 

Richland, Wash., Westinghouse Hanford Company, 

WHC-EP-0883, variously paginated.

Kinnison, H.B., and Sceva, J.E., 1963, Effects of hydraulic 

and geologic factors on streamflow of the Yakima River 

basin, Washington: U.S. Geological Survey Water-Supply 

Paper 1595, 134 p., accessed June 8, 2007, at http://pubs.

er.usgs.gov/usgspubs/wsp/wsp1595 

Kirk, T.K., and Mackie, T.L., 1993, Black Rock-Moxee 

Valley groundwater study: Washington State Department of 

Ecology, Open File Technical Report 93-1, 79 p., accessed 

June 8, 2007, at http://www.ecy.wa.gov/biblio/oftr9301.html

 Korosec, M.A., 1987, Geologic map of the Mount Adams 

quadrangle, Washington: Washington State Department of 

Natural Resources, Open-File Report 87-5, 41 p., 1 sheet, 

scale 1:100,000.

Kratz, M.R., 1978, Dilemmas, disruptions, but no disaster—

Drought in the Yakima basin, Washington, 1977: State 

Climatologist for Arizona Climatological Publications, 

Scientific Paper no. 3, 16 p.

Lane, R.C., and Whiteman, K.J., 1989, Ground-water levels 

spring 1985, and ground-water level changes spring 1983 to 

spring 1985, in three basalt units underlying the Columbia 

Plateau, Washington and Oregon: U.S. Geological Survey 

Water-Resources Investigations Report 88-4018, 4 pls., 

accessed February 5, 2008, at http://pubs.er.usgs.gov/

usgspubs/wri/wri884018

Larson, K.L., Keller, C.K., Larson, P.D., and Allen-King, 

R.M., 2000, Water resource implications of 18O and 2H 

distributions in basalt aquifer system: Groundwater, v. 38, 

p. 947-953.

Leake, S.A., Hoffman,J.P., and Dickinson, J.E., 2005, 

Numerical ground-water change model of the C aquifer 

and effects of ground-water withdrawals on stream 

depletion in selected reaches of Clear Creek, Chevelon 

Creek, and the Little Colorado River, northeastern Arizona: 

U.S. Geological Survey Scientific Investigations Report 

2005-5277, 29 p., accessed June 8, 2007, at http://pubs.usgs.

gov/sir/2005/5277/

Leavesley, G.H., Lichty, R.W., Troutman, B.M., and Saindon, 

L.G., 1983, Precipitation-runoff modeling system—

User’s manual: U.S. Geological Survey Water-Resources 

Investigations Report 83-4238, 207 p., accessed June 8, 

2007, at http://pubs.er.usgs.gov/usgspubs/wri/wri834238

Leavesley, G.H., Restrepo, P.J., Markstrom, S.L., Dixon, M., 

and Stannard, L.G., 1996, The modular modeling system 

(MMS)—User’s manual: U.S. Geological Survey Open-File 

Report 96-151, 142 p., accessed June 8, 2007, at http://pubs.

er.usgs.gov/usgspubs/ofr/ofr96151

Lindberg, J.W., and Bond, F.W., 1979, Geohydrology and 

ground-water quality beneath the 300 Area, Hanford Site, 

Washington: Richland, Wash., Battelle, Pacific Northwest 

Laboratory, PNL-2949 UC-70, 149 p.

Lindolm, G.F., 1996, Summary of the Snake River plain 

regional aquifer-system analysis, Idaho and eastern Oregon: 

U.S. Geological Survey Professional Paper 1408-A, 59 p., 

1 pl., accessed January 13, 2009, at http://pubs.er.usgs.gov/

usgspubs/pp/pp1408A

Lindolm, G.F., and Vaccaro, J.J., 1988, Region 2, Columbia 

Lava Plateau, in Back, William, Rosenshein, J.S., and 

Seaber, P.R., eds., Hydrogeology, v. O-2—The geology 

of North America: Boulder, Colo., Geological Society of 

America, p. 37-50.

Long, P.E., and Wood, B.J., 1986, Structures, textures, 

and cooling histories of Columbia River Basalt flows: 

Geological Society of America Bulletin, v. 97, no. 9, 

p. 1144-1155.

Loveland, T.R., Merchant, J., Ohlen, D.O., and Brown, J., 

1991, Development of a land cover characteristic data 

base for the conterminous United States: Photogrammetric 

Engineering and Remote Sensing, v. 57, no. 11, p. 

1453-1463.
86 Hydrogeologic Framework of the Yakima River Basin Aquifer System, Washington

Lum, W.E., II, Smoot, J.L., and Ralston, D.R., 1990, 

Geohydrology and numerical model analysis of groundwater flow in the Pullman-Moscow area, Washington 

and Idaho: U.S. Geological Survey Water-Resources 

Investigations Report 89-4103, 73 p., accessed June 8, 

2009, at http://pubs.er.usgs.gov/usgspubs/wri/wri894103

Lupton, J.E., 1983, Terrestrial Noble Gases: Isotope tracer 

studies and clues to primordial components in the mantle: 

Annual Review of Earth and Planetary Science Letters, 

v. 11, p. 371-414.

MacDonald, G.A., 1967, Forms and structures of Extrusive 

Basaltic Rocks: in Basalts—The Poldervaart treatise on 

rocks of basaltic composition, v. 1, H.H. Hess and A. 

Poldervaart, John, eds., New York, Wiley and Sons, p. 482.

Manga, Michael, 1996, Hydrology of streams in the Oregon 

Cascades: Water Resources Research, v. 32, no. 8, 

p. 2435-2439.

Manga, Michael, 1997, A model for discharge in springdominated streams and implications for transmissivity and 

recharge of Quaternary volcanics in the Oregon Cascades: 

Water Resources Research, v. 33, no. 8, p. 1813-1822.

Mastin, M.C., and Vaccaro, J.J., 2002, Watershed models for 

decision support in the Yakima River basin, Washington: 

U.S. Geological Survey Open-File Report 02-404, 46 p., 

accessed June 8, 2007, at http://pubs.usgs.gov/of/2002/

ofr02404

Mazor, Emanuel, 1991, Applied chemical and isotopic 

groundwater hydrology: Buckingham, United Kingdom, 

Open University Press, 273 p. 

McKinley, J.P., 1990, Alteration of Columbia River basalts and 

the chemical evolution of Columbia Plateau groundwaters: 

Albuquerque, N. Mex., University of New Mexico, Ph.D. 

dissertation, 277 p.

Meier, P.M., Carrera, Jesús, and Sánchez-Vila, Xavier, 1999, A 

numerical study on the relationship between transmissivity 

and specific capacity in heterogeneous aquifers: Ground 

Water, v. 37, no. 4, p. 611-617.

Meyers, C.W., and Price, S.M., 1979, Geologic studies of the 

Columbia Plateau, a status report: Rockwell International, 

Rockwell Hanford Operations RHO-BWI-ST-4, 520 p., 

36 pls.

Meyers, D.A., Last, G.V., and Freshley, M.D., 1985, Status 

report on the hydrogeologic conceptual model for the 

unconfined aquifer at the Hanford Site: Richland, Wash., 

Battelle Pacific Northwest Laboratories, letter report, 23 p.

Molenaar, Dee, 1961, Flowing artesian wells in Washington 

State: Olympia, Wash., Department of Conservation, 

Division of Water Resources, Water Supply Bulletin No. 16, 

115 p., 1 pl. 

Neuzil, C.E., 1994, How permeable are clays and shales?: 

Water Resources Research, v. 30, no. 2, p. 145-150. 

Newcomb, R.C., 1959, Some preliminary notes on ground 

water in the Columbia River Basalt: Northwest Science, 

v. 33, no. 1, p. 1-18. 

Newcomb, R.C., 1961, Storage of ground water behind 

subsurface dams in Columbia River Basalt, Washington, 

Oregon, and Idaho: U.S. Geological Professional Paper 

383-A, 15 p., accessed June 8, 2007, at http://pubs.er.usgs.

gov/usgspubs/pp/pp383A

Newcomb, R.C., 1969, Effect of tectonic structure on the 

occurrence of ground water in the basalt of the Columbia 

River Group of The Dalles area, Oregon and Washington: 

U.S. Geological Professional Paper 383-C, 33 p., accessed 

June 8, 2007, at http://pubs.er.usgs.gov/usgspubs/pp/

pp383C

Newcomb, R.C., 1970, Tectonic structure of the main part 

of the basalt of the Columbia River Group, Washington, 

Oregon, and Idaho: U.S. Geological Survey Miscellaneous 

Investigations Series, Map I-325, 2 sheets.

Newcomb, R.C., Strand, J.R., and Frank, F.J., 1972, Geology 

and ground-water characteristics of the Hanford Reservation 

of the U.S. Atomic Energy Commission, Washington: U.S. 

Geological Survey Professional Paper 717, 78 p., 3 pls., 

accessed June 8, 2007, at http://pubs.er.usgs.gov/usgspubs/

pp/pp717

Omernik, J.M., 1987, Ecoregions of the conterminous United 

States: Annals of the Association of American Geographers, 

v. 77, no. 1, p. 118-125.

Packard, F.A, Hansen, A.J., Jr., and Bauer, H.H., 1996, 

Hydrogeology and simulation of flow and the effects of 

development alternatives on the basalt aquifers of the Horse 

Heaven Hills, south-central Washington: U.S. Geological 

Survey Water-Resources Investigations Report 94-4068, 92 

p., 2 pls., accessed June 8, 2008, at http://pubs.er.usgs.gov/

usgspubs/wri/wri944068

Parker, G.L., and Storey, F.B., 1916, Water powers of 

the Cascade Range, Part III, Yakima River basin: U.S. 

Geological Survey Water Supply Paper 369, 169 p., 18 pls., 

accessed June 8, 2007, at http://pubs.er.usgs.gov/usgspubs/

wsp/wsp369

Phillips, W.M., and Walsh, T.J., 1987, Geologic map of the 

northwest part of the Goldendale quadrangle, Washington: 

Washington Division of Geology and Earth Resources, 

Open-File Report 87-13, 9 p., 1 sheet, scale 1:100,000.

Poeter, E., 1980, Mathematical models of the gamma-gamma 

and neutron epithermal neutron geophysical logging 

processes: Pullman, Wash., Washington State University, 

Ph.D. dissertation, 184 p.
Selected References 87

Polubarinova-Kochina, P.Ya., 1962, Theory of ground water 

movement—Translated by J.M. Roger De Wiest: New 

Jersey, Princeton University Press, Princeton, 613 p.

Prych, E.A., 1983, Numerical simulation of ground-water flow 

in Lower Satus Creek Basin, Yakima Indian Reservation, 

Washington: U.S. Geological Survey Water-Resources 

Investigations Report 82-4065, 78 p., accessed June 8, 

2008, at http://pubs.er.usgs.gov/usgspubs/wri/wri824065

Raymond, J.R., and Tillson, D.D., 1968, Evaluation of a thick 

basalt sequence in south-central Washington: Richland, 

Wash., Pacific Northwest National Laboratory, Battelle 

Memorial Institute, BNWL-776, 120 p.

Reidel, S.P., 1982, Stratigraphy of the Grande Ronde Basalt, 

Columbia River Basalt Group, from the lower Salmon 

River and northern Hells Canyon area, Idaho, Oregon, and 

Washington, in Bonnichsen, Bill and Breckenridge, R.M., 

eds., Cenozoic geology of Idaho: Idaho Bureau of Mines 

and Geology Bulletin 26, p. 77-101.

Reidel, S.P., and Fecht, K.R., 1994a, Geologic map of the 

Richland 1:100,000 quadrangle, Washington: Washington 

Division of Geology and Earth Resources, Open-File 

Report 94-8, 21 p., 1 sheet, scale 1:100,000.

Reidel, S.P., and Fecht, K.R., 1994b, Geologic map of 

the Priest Rapids 1:100,000 quadrangle, Washington: 

Washington Division of Geology and Earth Resources, 

Open-File Report 94-13, 22 p., 1 sheet, scale 1:100,000. 

Reidel, S.P., Johnson, V.G., and Spane, F.A., 2002, Natural 

gas storage in basalt aquifers of the Columbia Basin, Pacific 

Northwest USA: A guide to site characterization: Richland, 

Wash., Pacific Northwest National Laboratory, PNNL13962, 277 p., including Appendices A-H.

Rice, D.D., 1993, Biogenic gas—Controls, habitats, and 

resource potential, in Howell, D.G., ed., The future of 

energy gases: U.S. Geological Survey Professional Paper 

1570, p. 583-606, accessed June 8, 2009, at http://pubs.

er.usgs.gov/usgspubs/pp/pp1570

Schasse, H.W., 1987, Geologic map of the Mount Rainier 

quadrangle, Washington: Washington State Department of 

Natural Resources, Open-File Report 87-16, 43 p., 1 sheet, 

scale 1:100,000.

Schmidt, R.D., Johnson, Jennifer, and Didricksen, Kayti, 2007, 

Modeling groundwater hydrologic impacts of the potential 

Black River Reservoir: U.S. Bureau of Reclamation, 

Technical Series No. TS-YSS-10, 88 p.

Schuster, E.J., 1994a, Geologic maps of the east half of 

the Washington portion of the Goldendale 1:100,000 

quadrangle and the Washington portion of the Hermiston 

1:100,000 quadrangle: Washington State Department of 

Natural Resources, Open-File Report 94-9, 17 p., 1 sheet, 

scale 1:100,000.

Schuster, E.J., 1994b, Geologic map of the east half of the 

Toppenish 1:100,000 quadrangle, Washington: Washington 

State Department of Natural Resources, Open-File 

Report 94-10, 15 p., 1 sheet, scale 1:100,000.

Schuster, E.J., 1994c, Geologic map of the east half of the 

Yakima 1:100,000 quadrangle, Washington: Washington 

State Department of Natural Resources, Open-File 

Report 94-12, 19 p., 1 sheet, scale 1:100,000.

Skrivan, J.A., 1987, Ground-water hydrology of the Toppenish 

Creek Basin, Yakima Indian Reservation, Washington: U.S. 

Geological Survey Water-Resources Investigations Report 

82-4010, 47 p., accessed June 8, 2008, at http://pubs.er.usgs.

gov/usgspubs/wri/wri824010

Smith, G.A., 1988, Neogene synvolcanic and syntectonic 

sedimentation in central Washington: Geological Society of 

America Bulletin, v. 100, p. 1479-1492.

Smith, G.O., 1901, Geology and water resources of a portion 

of Yakima County, Washington: U.S. Geological Survey 

Water Supply and Irrigation Papers No. 55, 68 p., accessed 

June 8, 2007, at http://pubs.er.usgs.gov/usgspubs/wsp/

wsp55

Smoot, J.L., and Ralston, D.R., 1987, Hydrogeology and a 

mathematical model of ground-water flow in the PullmanMoscow region, Washington and Idaho: Moscow, Idaho, 

University of Idaho, Idaho Water Resources Research 

Institute, 118 p.

Solomon, D.K., 2000, 4He in ground water—Chapter 14, in

Cook, P.G., and Herczeg, A.L., eds., Environmental tracers 

in subsurface hydrology: Kluwer Academic Publishers 

p. 425-439.

Spane, F.A., Jr., and Thorne, P.D., 1985, The effects of 

drilling fluid invasion on hydraulic characterization of 

low-permeability basalt horizons—A field evaluation: 

Environmental Geology and Water Sciences, v. 7, no. 4, 

p. 227-236.

Spatial Climate Analysis Service–Oregon State University, 

2006, PRISM products matrix: Oregon State University 

database, accessed June 5, 2009, at http://www.prism.

oregonstate.edu/products/matrix.phtml
88 Hydrogeologic Framework of the Yakima River Basin Aquifer System, Washington

Steinkampf, W.C., Bortleson, G.C., and Packard, F.A., 1985, 

Controls on ground-water chemistry in the Horse Heaven 

Hills, south-central Washington: U.S. Geological Survey 

Water-Resources Investigations Report 85-4048, 26 p., 

accessed January 13, 2009, at http://pubs.er.usgs.gov/

usgspubs/wri/wri854048

Steinkampf, W.C., and Hearn, P.P., 1996, Ground-water 

geochemistry of the Columbia Plateau Aquifer System, 

Washington, Oregon, and Idaho: U.S. Geological Survey 

Open-File Report 95-467, 67 p., accessed January 13, 2009, 

at http://pubs.er.usgs.gov/usgspubs/ofr/ofr95467

Strait, S.R., and Mercer, R.B., 1987, Hydraulic property data 

from selected test zones on the Hanford Site: Richland, 

Wash., Rockwell International, Rockwell Hanford 

Operations, SD-BWI-DP-051, 44 p.

Stute, Martin, and Schlosser, Peter, 2000, Atmospheric noble 

gases—Chapter 11, in Cook, P.G., and Herczeg, A.L., eds., 

Environmental tracers in subsurface hydrology: Kluwer 

Academic Publishers, p. 249-278 

Sublette, W.R., 1986, Rock mechanics data package, Rev. 

1: Richland, Wash., Rockwell Hanford Operations Report 

SD-BWI-DP-041, 78 p.

Sumioka, S.S., 1998, A survey of ground-water quality in 

the Toppenish Creek basin, Yakima Indian Reservation, 

Washington, 1989–91: U.S. Geological Survey WaterResources Investigations Report 97-4194, 89 p., accessed 

April 8, 2008, at http://pubs.er.usgs.gov/usgspubs/wri/

wri974194

Swanson, D.A., Anderson, J.L., Bentley, R.D., Beverly, 

G.R., Camp, V.E., Gardner, J.N., and Wright, T.L., 1979a, 

Reconnaissance geologic map of the Columbia River 

Basalt group in eastern Washington and northern Idaho: 

U.S. Geological Survey Open-File Report 79-1363, 26 p., 

12 sheets, scale 1:250,000, accessed April 8, 2008, at http://

pubs.er.usgs.gov/usgspubs/ofr/ofr791363

Swanson, D.A., Brown, J.C., Anderson, J.L., Bentley, R.D., 

Beverly, G.R., Gardner, J.N., and Wright, T.L., 1979b, 

Preliminary structure contour maps on the top of the Grand 

Ronde and Wanapum Basalts, eastern Washington and 

northern Idaho: U.S. Geological Survey Open-File Report 

79-1364, 3 sheets, scale 1:250,000.

Swanson, D.A., and Wright, T.L., 1978, Bedrock geology of 

the southern Columbia Plateau and adjacent areas, Chap. 

3, in Baker, V.R., and Nummedal, D., eds., The channeled 

scabland: Washington, D.C., Planetary Geology Program, 

National Aeronautical and Space Administration, p. 37-57.

Systems Operations Advisory Committee, 1999, Report on 

biologically based flows for the Yakima River basin—

Report to The Secretary of the Interior, May 1999: Yakima, 

Wash., Systems Operation Advisory Committee, Executive 

Summary, 6 chapters and appendix. 

Tabor, R.W., Frizzell, V.A., Jr., Booth, D.B., Waitt, R.B., 

Whetten, J.T., and Zartman, R.E., 1993, Geologic map 

of the Skykomish River 30- by 60-minute quadrangle, 

Washington: U.S. Geological Survey Miscellaneous 

Investigations Series Map I-1963, 67 p., 1 sheet, scale 

1:100,000, accessed April 8, 2006, at http://pubs.er.usgs.

gov/usgspubs/i/i1963

Tabor, R.W., Frizzell, V.A., Jr., Whetten, J.T., Waitt, R.B., 

Swanson, D.A., Beverly, G.R., Booth, D.B., Hetherington, 

M.J., and Zartman, R.E., 1987, Geologic map of the Chelan 

30-minute by 60-minute quadrangle, Washington: U.S. 

Geological Survey Miscellaneous Investigations Series 

Map I-1661, 33 p., 1 sheet, scale 1:100,000, accessed 

April 8, 2006, at http://pubs.er.usgs.gov/usgspubs/i/i1661

Tabor, R.W., Waitt, R.B., Jr., Frizzell, V.A., Jr., Swanson, D.A., 

Byerly, G.R., and Bentley, R.D., 1982, Geologic map of 

the Wenatchee 1:100,000 quadrangle, central Washington: 

U.S. Geological Survey Miscellaneous Investigations 

Series Map I-1311, 26 p., 1 sheet, scale 1:100,000, accessed 

April 8, 2006, at http://pubs.er.usgs.gov/usgspubs/i/i1311

Tanaka, H., Barrett, G., and Wildrick, Linton, 1979, Regional 

basalt hydrology of the Columbia Plateau in Washington: 

Richland, Wash., Rockwell Hanford Operations, RHOBWI-C-60, 304 p., 19 pls.

Tanaka, H.H., Hansen, A.J., and Skrivan, J.A., 1974, Digital 

model study of ground-water hydrology, Columbia Basin 

Irrigation Project area, Washington: Olympia, Wash., 

Washington State Department of Ecology, Water Supply 

Bulletin 40, 60 p.

Theis, C.V., 1935, The relation between the lowering of the 

piezometric surface and the rate and duration of discharge 

of a well using groundwater storage: American Geophysical 

Union Transactions, v. 16, p. 519-524.

Theis, C.V., 1940, The source of water derived from wells—

Essential factors controlling the response of an aquifer to 

development: Civil Engineering, v. 10, p. 277-280.

Thorne, P.D., and Newcomer, D.R., 1992, Summary and 

evaluation of available hydraulic property data for the 

Hanford Site unconfined aquifer system: Richland, Wash., 

Pacific Northwest Laboratory, PNL-8337, variously 

paginated.
Selected References 89

Tolan, T.L., Reidel, S.P., Beeson, M.H., Anderson, J.L., Fecht, 

K.R., and Swanson, D.A., 1989, Revisions to the estimates 

of the areal extent and volume of the Columbia River Basalt 

Group, in, Reidel, S.P., and Hooper, P.R., eds., Volcanism 

and tectonism in the Columbia River flood-basalt province: 

Boulder, Colo., Geological Society of America, Special 

Paper 239, p. 1-20.

Tomkeieff, S.I., 1940, The basalt lavas of the Giant’s 

Causeway district of Northern Ireland: Bulletin 

Volcanologique, v. 6, p. 89-143.

Toth, J., 1963a, A theoretical analysis of groundwater flow 

in small drainage basins: Proceedings of Hydrology 

Symposium No. 3, Groundwater, Ottawa, Canada, Queen’s 

Printer, p. 75-96. 

Toth, J., 1963b, A theoretical analysis of groundwater flow in 

small drainage basins: Journal Geophysical Research, v. 68, 

no. 16, p. 4795-4812.

Toth, J., 1978, Gravity-induced cross-formational flow of 

formation fluids, Red Earth region, Alberta, Canada—

Analysis, patterns, and evolution: Water Resources 

Research, v. 14, no. 5, p. 805-843.

 Trainer, F.W., 1988, Plutonic and metamorphic rocks, in

Back, William, Rosenshein, J.S., and Seaber, P.R., eds., 

Hydrogeology, v. O-2—The geology of North America: 

Boulder, Colo., Geological Society of America, p. 367-380.

U.S. District Court, 1945, Consent decree in the District Court 

of the United States for the Eastern District of Washington, 

Southern Division: Spokane, Wash., Civil action no. 21. 

U.S. Geological Survey, 1975, Water resources of the 

Toppenish Creek basin, Yakima Indian Reservation, 

Washington: U.S. Geological Survey Water-Resources 

Investigations 74-42, 144 p.

U.S. Geological Survey, 2000, National elevation dataset: 

U.S. Geological Survey database, accessed June 8, 2007, at 

http://edc.usgs.gov/products/elevation/ned.html

U.S. Geological Survey, 2006, National field manual for the 

collection of water-quality data: U.S. Geological Survey 

Techniques of Water-Resources Investigations Book 9, 

accessed November 13, 2008, at http://pubs.water.usgs.gov/

twri9A/.

Vaccaro, J.J., 1995, Changes in the hydrometeorological 

regime in the Pacific Northwest, 1995: Proceedings of 

the Twelfth Annual Pacific Climate Workshop, Asilomar, 

California, Technical Report 46 of the Interagency 

Ecological Program for the Sacramento-San Joaquin 

Estuary, p. 143.

Vaccaro, J.J., 1999, Summary of the Columbia Plateau 

Regional Aquifer-System analysis, Washington, Oregon, 

and Idaho: U.S. Geological Survey Professional Paper 

1413-A, 51 p., accessed June 8, 2007, at http://pubs.er.usgs.

gov/usgspubs/pp/pp1413A

Vaccaro, J.J., 2002, Interdecadal changes in the 

hydrometeorological regime of the Pacific Northwest and 

in the regional-to-hemispheric climate regimes, and their 

linkages, 2002: U.S. Geological Survey Water-Resources 

Investigations Report 02-4176, 94 p., accessed August, 

2007, at http://pubs.er.usgs.gov/usgspubs/wri/wri024176

Vaccaro, J.J., 2007, A deep percolation model for estimating 

ground-water recharge—Documentation of modules for the 

Modular Modeling System of the U.S. Geological Survey: 

Scientific Investigations Report 2006-5318, 29 p., accessed 

June 8, 2007, at http://pubs.er.usgs.gov/usgspubs/sir/

sir20065318

Vaccaro, J.J., Hansen, A.J., and Jones, M.A., 1999, 

Hydrogeologic framework of the Puget Sound Aquifer 

System, Washington and British Columbia: U.S. Geological 

Survey Professional Paper 1424-D, 64 p., 1 pl., accessed 

April 22, 2008, at http://pubs.er.usgs.gov/usgspubs/pp/

pp1424D

Vaccaro, J.J., Keys, M.E., Julich, R.J., and Welch, W.B., 2008, 

Thermal profiles for selected river reaches in the Yakima 

River Basin, Washington: U.S. Geological Survey Data 

Series 342, accessed May 2, 2008, at http://pubs.usgs.gov/

ds/342

Vaccaro, J.J., and Maloy, K.J., 2006, A method to thermally 

profile long river reaches to identify potential areas of 

ground-water discharge and preferred salmonid habitat: 

U.S. Geological Survey Scientific Investigations Report 

2006-5136, 16 p., accessed October 8, 2008, at http://pubs.

usgs.gov/sir/2006/5136/.

Vaccaro, J.J., and Olsen, T.D., 2007a, Estimates of 

ground-water recharge to the Yakima Basin Aquifer 

System, Washington: U.S. Geological Survey Scientific 

Investigations Report 2007-5007, 30 p., accessed June 8, 

2007, at http://pubs.er.usgs.gov/usgspubs/sir/sir20075007

Vaccaro, J.J., and Olsen, T.D., 2007b, Estimates of monthly 

ground-water recharge to the Yakima Basin Aquifer 

System, Washington, 1960–2001, for current land-use and 

land-cover conditions: U.S. Geological Survey Open-File 

Report 2007-1238, 2 p., accessed August, 2007, at http://

pubs.water.usgs.gov/ofr20071238

Vaccaro, J.J., and Sumioka, S.S., 2006, Estimates of 

ground-water pumpage from the Yakima Basin Aquifer 

System, Washington, 1960–2000: U.S. Geological Survey 

Scientific Investigations Report 2006-5205, 56 p., accessed 

October 2007, at http://pubs.usgs.gov/sir/2006/5205
90 Hydrogeologic Framework of the Yakima River Basin Aquifer System, Washington

Vermeul, V.R., Bergeron, M.P., Cole, C.R., Murray, C.J., 

Nichols, W.E., Scheibe, T.D., Thorne, P.D., Waichler, S.R., 

and Xie, Y., 2003, Transient inverse calibration of the sitewide groundwater flow model (ACM-2)—FY03 progress 

report: Richland, Wash., Pacific Northwest National 

Laboratory, PNNL-14398, variously paginated. 

Vermeul, V.R., Cole, C.R., Bergeron, M.P., Thorne, P.D., 

and Wurstner, S.K., 2001, Transient inverse calibration 

of site-wide groundwater model to Hanford Operational 

Impacts from 1943 to 1996—Alternative conceptual model 

considering interaction with uppermost basalt confined 

aquifer: Richland, Wash., Pacific Northwest National 

Laboratory, PNNL-13623, variously paginated.

Wagner, R.A., and Lane, R.C., 1994, Selected ground-water 

information for the Columbia Plateau regional aquifer 

system, Washington and Oregon, 1982–1985—Volume 

3. Water-quality: U.S. Geological Survey Open-File 

Report 93-359, 226 p.

Walsh, T.J., 1986a, Geologic map of the west half of the 

Toppenish quadrangle, Washington: Washington Division of 

Geology and Earth Resources, Open-File Report 86-3, 8 p., 

1 sheet, scale 1:100,000.

Walsh, T.J., 1986b, Geologic map of the west half of the 

Yakima quadrangle, Washington: Washington Division 

of Geology and Earth Resources, Open-File Report 86-4, 

12 p., 1 sheet, scale 1:100,000.

Walsh, T.J., and Lingley, W.S., 1991, Coal maturation and 

natural gas potential of western and central Washington: 

Washington State Department of Natural Resources, 

Olympia, Wash., Open-File Report 91-2, 27 p. 

Waring, G.A., 1913, Geology and water resources of a portion 

of south-central Washington: U.S. Geological Survey Water 

Supply Paper 316, 46 p., accessed June 8, 2007, at http://

pubs.er.usgs.gov/usgspubs/wsp/wsp316

Washington State Department of Ecology, 1998, Washington 

State Water Law, A primer: Washington State Department 

of Ecology, WR-98-152, accessed October 2000, at http://

www.ecy.wa.gov/pubs/98152

Washington State Department of Natural Resources, 2002, 

Digital Geology of Washington State, 1:1100,000-scale 

quadrangles, April 30, 2002: Washington Department of 

Natural Resources 7/10/2000, digital media.

Waters, A.C., 1960, Determining direction of flow in basalts: 

American Journal of Science, v. 258, p. 350-366.

Whiteman, K.J., Vaccaro, J.J., Gonthier, J.B., and Bauer, H.H., 

1994, The hydrogeologic framework and geochemistry of 

the Columbia Plateau Aquifer System, Washington, Oregon, 

and Idaho: U.S. Geological Survey Professional Paper 

1413-B, 73 p.: accessed February 11, 2008, at http://pubs.

er.usgs.gov/usgspubs/pp/pp1413B

Williamson, A.K., and Grubb, H.F., 2001, Ground-water flow 

in the Gulf Coast aquifer systems, south-central United 

States: U.S. Geological Survey Professional Paper 1416-F, 

173 p., accessed September 10, 2007, at http://pubs.er.usgs.

gov/usgspubs/pp/pp1416F

Wood, W.W., and Fernandez, L.A., 1988, Volcanic rocks, 

Chapter 39, in, Back, W., Rosenshein, J.S., and Seaber, 

P.R., eds., Hydrogeology, v. O-2—The Geology of North 

America: Boulder, Col., Geological Society of America, 

p. 353-365.

Woodward, D.G., Gannett, M.W., and Vaccaro, J.J., 1998, 

Hydrogeologic framework of the Willamette Lowland 

Aquifer System, Oregon and Washington: U.S. Geological 

Survey Professional Paper 1424-B, 82 p., 1 pl., accessed 

April 22, 2008, at http://pubs.er.usgs.gov/usgspubs/pp/

pp1424B

Wurstner, S.K., Thorne, P.D., Chamness, M.A., Freshley, 

M.D., and Williams, M.D., 1995, Development of a 

three-dimensional groundwater model of the Hanford 

Site unconfined aquifer system—FY 1995 status report: 

Richland, Wash., Pacific Northwest Laboratory, PNL10886, variously paginated.

Zimmerman, D.A., 1983, Report on task 2 of modeling task 

force support—Interpret and revise conceptual model—

Data documentation from the extended Pasco basin model: 

Richland, Wash., Pacific Northwest Laboratory.
Appendix A 91

Appendix A. Methods and Assumptions Used to Estimate Lateral Hydraulic 

Conductivity from Specific-Capacity Data

The modified Theis equation (Ferris and others, 1962, p. 

99) was used to estimate transmissivity of the pumped interval 

for wells with a screened or perforated interval. Transmissivity 

is the product of hydraulic conductivity and thickness of the 

part of the hydrogeologic unit supplying water to the well. The 

modified equation is

2

2.25 ln , 4

where

is drawdown in the well, in feet;

is discharge, or pumping rate, of the well,

in cubic feet per day;

is transmissivity of the hydrogeologic unit,

 in foot squared per day;

is le

Q Tt

s

T S

s

Q

T

t

r = π

ngth of time the well was pumped,

in days;

is radius of the well, in feet; and

is storage coefficient, a dimensionless

number, assumed to be 0.0001 for basalt

and bedrock units and 0.1 for overburden

unit

r

S

s.

(1)

Assumptions for using equation 1 are that aquifers are 

homogeneous, isotropic, and infinite in extent; wells are 

fully penetrating; flow to the well is lateral; steady-state 

drawdown has been achieved; and water is released from 

storage instantaneously. Additionally, for unconfined aquifers, 

drawdown is assumed to be small in relation to the saturated 

thickness of the aquifer. Although many of the assumptions 

are not precisely met, the field conditions in the study area 

approximate most of the assumptions and the calculated 

hydraulic conductivities are reasonable estimates. 

A computer program was used to solve equation 1 for 

transmissivity (T) using Newton’s iterative method (Carnahan 

and others, 1969). The iterative approach is necessary because 

T cannot be easily solved by a direct solution method. Next, 

the following equation was used to calculate hydraulic 

conductivity:

= ,

where

is lateral hydraulic conductivity of the geologic

material in the vicinity of the well opening,

in feet per day; and

is thickness, in feet, approximated using the 

length of the open interv

h

h

T K

b

K

b

al as reported in the

driller's report.

(2)

The use of the length of a well’s open interval for b may 

overestimate values of Kh because the equations assume that 

all the water flows laterally within a layer of this thickness. 

Although some of the flow will be outside this region, the 

amount can be expected to be small because in most deposits, 

vertical flow is inhibited by layering. The difference in 

computed transmissivity between using 0.1 and 0.0001 for the 

storage coefficient is a factor of only about 2. For wells for 

which no data were available for the screen interval or time of 

pumping, a value of 100 ft and 1 hour, respectively, were used.
92 Hydrogeologic Framework of the Yakima River Basin Aquifer System, Washington Appendix B.

Hydrochemical Data from Groundwater Samples, Yakima River Basin Aquifer System, 

WashingtonTable B1. Hydrochemical data from groundwater samples, September 1990 through August 2005, Yakima River basin aquifer system, Washington.[Hydrogeologic unit: CN,consolidated deposits (Ellensburg Formation); GR, Grande Ronde; SM, Saddle Mountains; UNCON, unconsolidated deposits-mainly alluvium; WN, Wanapum. Abbreviations:

NGVD 29, National Geodetic Vertical Datum of 1929; E, estimated value below the long term detection limit; M, presence of material verified but not quantified; DIC, dissolved inorganic carbon; PMC, percent modern carbon; NTU, Nephalometric Turbidity Unit; TU, tritium units; ccSTP/g, cubic centimeter at standard temperature and pressure per gram water; oC, degrees Celsius; mg/L, milligram per liter; μS/cm, microseimens per centimeter; μg/L, microgram per liter; δ, delta stable isotpe abundance; <, less than; –, no data available]

Well No. Collection

agency

Date Hydrogeo- logic unit

Land-surface 

altitude 

(feet above 

NGVD 29)

Hole

depth 

(ft)

Well

depth 

(ft)

Temperature

(oC)

Specific

conductance

(μS/cm)

pH

Dissolved

oxygen

(mg/L)

Total 

dissolved

solids

Turbidity

(NTU)

Carbonate

(mg/L)

Bicarbonate

(mg/L)

08N-24E-01J01 USGS 09-27-00 WN 734 1,264 1,033 21.1 403 8.6

M – – – –

08N-28E-09F01 USGS 09-05-01 WN 935 1,262 920 25.3 438 8.1 <0.1 – – – –

09N-23E-22J01 USGS 09-04-01 SM-WN 827 1,632 308 18.5 410 7.7 4.0 – – – –

09N-23E-22L01 USGS 09-05-01 WN 770 1,294 739 25.6 405 9.2 <.1 – – – –

09N-27E-24N01 USGS 09-05-01 WN 830 1,378 922 23.7 410 8.4 <.1 – – – –

10N-16E-19H01D1 USGS 09-11-01 GR 1,540 425 30 20.0 265 7.5 8.0 – – – –

10N-16E-21D01 USGS 09-11-01 CN 1,390 158 111 14.2 207 7.2 <.1 – – – –

10N-17E-27Q01 USGS 09-07-01 SM-WN-GR 1,120 1,510 134 – 425 7.2 – – – – –

10N-20E-04L01 USGS 09-07-01 CN 760 1,020 810 22.4 209 7.9 .1 – – – –

10N-20E-09A01 USGS 09-07-01 CN 757 863 783 20.1 162 7.9 <.1 – – – –

10N-20E-09A02 USGS 09-07-01 CN 760 250 138 15.2 119 8.2 4.5 – – – –

10N-22E-25F03 USGS 02-27-00 WN 748 1,701 1,283 25.3 310 8.5 .0 – – – –

11N-18E-26M03 USGS 09-06-01 WN 835 1,471 1,385 30.5 335 7.7

M – – – –

11N-18E-27H01 USGS 02-12-01 CN 840 111 111 – 376 7.6 8.8 – – – –

11N-21E-34F01 USGS 09-12-01 CN 970 198 195 15.5 997 7.6 8.6 – – – –

11N-22E-30C01 USGS 09-06-01 GR 1,220 2,715 2,049 28.8 333 9.1

M – – – –

11N-22E-33M01 USGS 09-12-01 SM 1,130 1,105 702 22.0 281 8.1 <.1 – – – –

12N-20E-12K01 USGS 08-24-05 GR 1,435 2,700 1,550 31.6 319 8.7 <.1 – – – –

13N-20E-34Q01D1 USGS 08-24-05 WN 1,548 540 – 23.6 347 7.9 <.1 – – – –13N-27E-26H01 USGS 09-12-01 GR 402 4,340 2,260 20.2 1,230 10.0 <.1 – – – –

13N-20E-33N01 USGS 10-01-04 WN 1,285 1,628 1,000 – 273 8.0 .1 – – – –

11N-19E-06N Yakama Nation 02-28-91 UNCON 885 53 50 14.3 316 7.0 7.6 114 1.2 <1.0 163

11N-19E-34A01 Yakama Nation 02-28-91 UNCON 815 62 57 13.5 269 6.9 8.2 82.0 .2 <1.0 28.0

11N-19E-34B01A Yakama Nation 04-10-91 UNCON 815 226 216 15.7 132 7.4 6.0 120 32 <1.0 74

11N-18E-03E Yakama Nation 03-06-91 UNCON 940 195 190 12.6 860 7.3 5.2 573 .5 <1.0 439

11N-18E-20R02A Yakama Nation 04-15-91 UNCON 860 45 35 13.9 639 7.2 1.9 532 29 <1.0 340

11N-18E-20R02B Yakama Nation 04-15-91 UNCON 860 64 58 13.6 621 7.3 2.0 484 4.5 <1.0 33.0

11N-17E-23D02 Yakama Nation 03-06-91 UNCON 890 95 90 13.4 366 7.0 6.6 344 .6 <1.0 153

11N-16E-23B02 Yakama Nation 03-06-91 UNCON 1,185 90 85 11.2 345 6.9 3.8 324 .2 <1.0 209
Appendix B

93

Table B1. Hydrochemical data from groundwater samples, Yakima River basin aquifer system, Washington.—Continued[Hydrogeologic unit: CN,consolidated deposits (Ellensburg Formation); GR, Grande Ronde; SM, Saddle Mountains; UNCON, unconsolidated deposits-mainly alluvium; WN, Wanapum. Abbreviations:

NGVD 29, National Geodetic Vertical Datum of 1929; E, estimated value below the long term detection limit; M, presence of material verified but not quantified; DIC, dissolved inorganic carbon; PMC, percent modern carbon; NTU, Nephalometric Turbidity Unit; TU, tritium units; ccSTP/g, cubic centimeter at standard temperature and pressure per gram water; oC, degrees Celsius; mg/L, milligram per liter; μS/cm, microseimens per centimeter; μg/L, microgram per liter; δ, delta stable isotpe abundance; <, less than; –, no data available]

Well No. Collection

agency

Date Alkalinity (mg/L) Potassium (mg/L) Manga- nese (mg/L) Magne- sium (mg/L) Calcium (mg/L) Boron (mg/L) Phosphate (dissolved) (mg/L) Total phos- phorus (mg/L) Nitrite (mg/L) Nitrite + nitrate as N (mg/L) Ammonia as N (mg/L) Sulphate (mg/L)

08N-24E-01J01 USGS 09-27-00 239 15.8 – 3.94 10.9 – – – – – – 0.59

08N-28E-09F01 USGS 09-05-01 220 13.5 – 6.92 15.9 – – – – <0.05 – 30.1

09N-23E-22J01 USGS 09-04-01 163 5.02 – 14.1 42.3 – – – – 4.48 – 41.5

09N-23E-22L01 USGS 09-05-01 212 9.98 – .04 .86 – – – – <.05 – .64

09N-27E-24N01 USGS 09-05-01 212 14.1 – 2.13 8.61 – – – – <.05 – 10.7

10N-16E-19H01D1 USGS 09-11-01 161 4.23 – 13.5 25.0 – – – – .3 – 3.22

10N-16E-21D01 USGS 09-11-01 116 2.95 – 10.3 19.7 – – – – .4 – 2.77

10N-17E-27Q01 USGS 09-07-01 – 6.35 – 17.6 26.8 – – – – <.05 – .25

10N-20E-04L01 USGS 09-07-01 131 5.22 – 5.07 12.6 – – – – <.05 – E.06

10N-20E-09A01 USGS 09-07-01 107 3.38 – 3.05 11.1 – – – – E.03 – E.09

10N-20E-09A02 USGS 09-07-01 65.0 1.66 – 3.52 12.6 – – – – .39 – 2.74

10N-22E-25F03 USGS 02-27-00 171 14.0 – .62 3.17 – – – – – – 2.62

11N-18E-26M03 USGS 09-06-01 – 7.90 – 11.8 21.8 – – – – – – .16

11N-18E-27H01 USGS 02-12-01 144 4.75 – 12.9 34.9 – – – – 1.62 – 28.9

11N-21E-34F01 USGS 09-12-01 – 5.17 – 33.2 107 – – – – 17.4 – 139

11N-22E-30C01 USGS 09-06-01 – 10.3 – .17 2.52 – – – – <.05 – .38

11N-22E-33M01 USGS 09-12-01 – 6.56 – 9.34 25.4 – – – – E.03 – 29.9

12N-20E-12K01 USGS 08-24-05 160 7.79 – .60 3.31 – – – – <.06 – .33

13N-20E-34Q01D1 USGS 08-24-05 157 6.63 – 11.1 20.7 – – – – <.06 – 14.4

13N-27E-26H01 USGS 09-12-01 – 6.43 – E.004 1.87 – – – – <.05 – 123

13N-20E-33N01 USGS 10-01-04 142 8.61 – 4.46 11.5 – – – – <.06 – E.14

11N-19E-06N Yakama Nation 02-28-91 134 3.00 – 11.0 32.0 <0.1 0.06 0.06 <0.002 2.40 <0.07 15.8

11N-19E-34A01 Yakama Nation 02-28-91 23.0 3.00 – 10.0 27.0 <.1 .09 .09 <.002 3.20 <.07 8.70

11N-19E-34B01A Yakama Nation 04-10-91 61.0 2.00 – 2.70 11.0 .1 <.05 .05 <.002 .60 .56 5.80

11N-18E-03E Yakama Nation 03-06-91 360 3.00 – 35.0 76.0 <.1 <.05 <.05 <.002 1.70 <.07 87.411N-18E-20R02A Yakama Nation 04-15-91 280 5.00 0.13 21.0 64.0 <.1 .12 .09 <.002 6.50 <.07 37.0

11N-18E-20R02B Yakama Nation 04-15-91 270 3.00 .02 24.0 58.0 <.1 .08 .08 <.002 4.60 <.07 29.8

11N-17E-23D02 Yakama Nation 03-06-91 125 2.00 <.01 16.0 31.0 <.1 .09 .08 <.002 1.10 <.07 41.5

11N-16E-23B02 Yakama Nation 03-06-91 171 4.00 <.01 14.0 23.0 <.1 .15 .17 <.002 .60 <.07 6.80
94 Hydrogeologic Framework of the Yakima River Basin Aquifer System, Washington Table B1. Hydrochemical data from groundwater samples, Yakima River basin aquifer system, Washington.—Continued

[Hydrogeologic unit: CN,consolidated deposits (Ellensburg Formation); GR, Grande Ronde; SM, Saddle Mountains; UNCON, unconsolidated deposits-mainly alluvium; WN, Wanapum. Abbreviations:

NGVD 29, National Geodetic Vertical Datum of 1929; E, estimated value below the long term detection limit; M, presence of material verified but not quantified; DIC, dissolved inorganic carbon; PMC, percent modern carbon; NTU, Nephalometric Turbidity Unit; TU, tritium units; ccSTP/g, cubic centimeter at standard temperature and pressure per gram water; oC, degrees Celsius; mg/L, milligram per liter; μS/cm, microseimens per centimeter; μg/L, microgram per liter; δ, delta stable isotpe abundance; <, less than; –, no data available]

Well No. Collection

agency

Date Chloride (mg/L) Sodium (mg/L) SiO2 (mg/L) Fluoride (mg/L)

Dissolved 

organic 

carbon

(mg/L)

δ18O

(per mil)

δD

(per mil)

Tritium

(TU)

14C DIC

(PMC)

δ13C DIC

(per mil)

Hydrogen

sulfide

(mg/L)

Oxidation 

reduction 

potential

(millivolts)

08N-24E-01J01 USGS 09-27-00 8.88 75.5 64.6 0.91 0.40 -17.2 -133 1.28 19.2 -15.5 – -287

08N-28E-09F01 USGS 09-05-01 9.48 62.3 68.0 .93 .90 -17.9 -141 .19 5.57 -13.4 0.19 -324

09N-23E-22J01 USGS 09-04-01 13.6 15.7 60.3 .4 1.0 -15.7 -129 .41 28.0 -12.3 -- -324

09N-23E-22L01 USGS 09-05-01 20.5 84.9 80.5 2.75 .70 -18.4 -144 .06 2.03 -1.37 .37 –09N-27E-24N01 USGS 09-05-01 17.4 71.1 68.0 1.44 1.0 -17.9 -139 .50 3.87 -5.99 .01 -388

10N-16E-19H01D1 USGS 09-11-01 1.64 8.18 61.3 E.15 .50 -15.2 -116 .13 85.2 -16.9 – -286

10N-16E-21D01 USGS 09-11-01 2.28 6.23 53.9 E.14 .50 -15.1 -114 1.53 89.2 -16.9 – –

10N-17E-27Q01 USGS 09-07-01 4.74 39.7 89.5 .90 1.3 -16.7 -130 .00 3.22 -8.52 – -220

10N-20E-04L01 USGS 09-07-01 3.02 22.4 71.9 .65 .30 -16.3 -124 .13 11.4 -12.1 .08 -20310N-20E-09A01 USGS 09-07-01 2.2 17.5 65.0 .55 1.0 -15.8 -118

M 21.8 -13.3 .01 -205

10N-20E-09A02 USGS 09-07-01 1.26 5.69 23.7 <.20 .80 -14.4 -106 1.38 84.5 -13.5 – 45.0

10N-22E-25F03 USGS 02-27-00 8.85 64.5 69.6 1.05 .20 -18.2 -144 .00 7.20 -11.1 .62 -307

11N-18E-26M03 USGS 09-06-01 4.77 34.6 83.4 .80 1.8 -17.7 -138 .00 5.30 -11.5 .01 -234

11N-18E-27H01 USGS 02-12-01 10.2 21.7 55.2 .17 .60 -16.9 -132 .00 38.8 -11.6 <.01 24.1

11N-21E-34F01 USGS 09-12-01 46.1 38.2 43.8 .26 2.7 -15.6 -129 12.0 91.8 -13.7 – –

11N-22E-30C01 USGS 09-06-01 12.1 68.3 46.6 6.08 7.0 -18.2 -143 .06 1.32 2.80 .07 130

11N-22E-33M01 USGS 09-12-01 5.46 15.1 54.9 .48 .30 -15.6 -128 .16 20.1 -11.8 <.01 --

12N-20E-12K01 USGS 08-24-05 4.83 63.2 84.2 1.48 E.30 -17.8 -139 .00 1.99 -5.36 .07 -16013N-20E-34Q01D1 USGS 08-24-05 7.11 36.1 68.7 .85 .44 -17.1 -135 .16 12.3 -10.6 .03 -20.7

13N-27E-26H01 USGS 09-12-01 146 255 119 38.9 3.8 -14.5 -120 .00 – -20.0 1.60 -350

13N-20E-33N01 USGS 10-01-04 4.79 40.4 66.2 1.06 .40 -17.4 -137 .09 9.83 -8.71 – –

11N-19E-06N Yakama Nation 02-28-91 5.80 13.0 31.0 <.20 .91 -14.5 -105 10.1 – – – –

11N-19E-34A01 Yakama Nation 02-28-91 3.90 10.0 31.0 <.20 .74 -13.9 -107 9.50 – – – –

11N-19E-34B01A Yakama Nation 04-10-91 1.80 14.0 22.0 <.20 .30 -15.0 -105 .00 – – – –

11N-18E-03E Yakama Nation 03-06-91 23.6 62.0 54.0 .50 3.2 -15.3 -114 9.95 98.7 -13.9 – –

11N-18E-20R02A Yakama Nation 04-15-91 13.9 34.0 34.0 .30 1.3 -14.5 -106 19.9 – – – –

11N-18E-20R02B Yakama Nation 04-15-91 11.0 43.0 43.0 .30 1.1 -14.6 -108 26.9 – – – –

11N-17E-23D02 Yakama Nation 03-06-91 20.0 20.0 55.0 .40 1.0 -15.8 -122 1.10 – – – –

11N-16E-23B02 Yakama Nation 03-06-91 3.30 25.0 48.0 .40 .60 -15.6 -115 9.00 – – – –
Appendix B

95

Table B1. Hydrochemical data from groundwater samples, Yakima River basin aquifer system, Washington.—Continued[Hydrogeologic unit: CN,consolidated deposits (Ellensburg Formation); GR, Grande Ronde; SM, Saddle Mountains; UNCON, unconsolidated deposits-mainly alluvium; WN, Wanapum. Abbreviations:

NGVD 29, National Geodetic Vertical Datum of 1929; E, estimated value below the long term detection limit; M, presence of material verified but not quantified; DIC, dissolved inorganic carbon; PMC, percent modern carbon; NTU, Nephalometric Turbidity Unit; TU, tritium units; ccSTP/g, cubic centimeter at standard temperature and pressure per gram water; oC, degrees Celsius; mg/L, milligram per liter; μS/cm, microseimens per centimeter; μg/L, microgram per liter; δ, delta stable isotpe abundance; <, less than; –, no data available]

Well No. Collection

agency

Date Nitrogen (mg/L) Argon (ccSTP/g) Neon (ccSTP/g) Hellium (ccSTP/g) Krypton (ccSTP/g) Xenon (ccSTP/g) Methane (mg/L) δ13C-CH4 (per mil)

08N-24E-01J01 USGS 09-27-00 – – – – – – – –08N-28E-09F01 USGS 09-05-01 18.8 – – – – – 2.38 -45.4

09N-23E-22J01 USGS 09-04-01 19.1 – – – – – .88 -32.7

09N-23E-22L01 USGS 09-05-01 1.81 – – – – – 42.7 -35.5

09N-27E-24N01 USGS 09-05-01 11.0 – – – – – 49.8 -35.1

10N-16E-19H01D1 USGS 09-11-01 – – – – – – – –10N-16E-21D01 USGS 09-11-01 20.0 4.09E-04 2.47E-07 6.34E-08 8.92E-08 1.29E-08 <.01 –

10N-17E-27Q01 USGS 09-07-01 12.6 2.99E-04 1.82E-07 8.58E-07 6.99E-08 1.06E-08 10.3 -43.110N-20E-04L01 USGS 09-07-01 17.3 3.69E-04 2.06E-07 5.29E-07 8.29E-08 1.22E-08 4.49 -9.8710N-20E-09A01 USGS 09-07-01 17.9 3.76E-04 2.11E-07 2.90E-07 8.30E-08 1.24E-08 <.01 -53.0

10N-20E-09A02 USGS 09-07-01 18.2 3.90E-04 2.19E-07 5.15E-08 8.63E-08 1.27E-08 2.1 –

10N-22E-25F03 USGS 02-27-00 8.70 – – – – – 16.0 –

11N-18E-26M03 USGS 09-06-01 16.9 3.57E-04 2.03E-07 1.45E-06 8.42E-08 1.20E-08 8.17 -52.3

11N-18E-27H01 USGS 02-12-01 21.5 – – – – – – –

11N-21E-34F01 USGS 09-12-01 20.5 3.66E-04 3.04E-07 7.47E-08 7.74E-08 1.12E-08 – –

11N-22E-30C01 USGS 09-06-01 2.10 – – – – – 38.3 -35.6

11N-22E-33M01 USGS 09-12-01 18.4 3.47E-04 2.09E-07 1.11E-07 7.70E-08 1.17E-08 .04 –

12N-20E-12K01 USGS 08-24-05 8.20 – – – – – 25.7 –

13N-20E-34Q01D1 USGS 08-24-05 11.1 – – – – – 16.5 –

13N-27E-26H01 USGS 09-12-01 20.5 3.77E-04 2.22E-07 1.60E-05 8.08E-08 1.16E-08 .10 –

13N-20E-33N01 USGS 10-01-04 15.6 – – – – – 8.70 –

11N-19E-06N Yakama Nation 02-28-91 – – – – – – – –

11N-19E-34A01 Yakama Nation 02-28-91 – – – – – – – –11N-19E-34B01A Yakama Nation 04-10-91 – – – – – – – –11N-18E-03E Yakama Nation 03-06-91 – – – – – – – –11N-18E-20R02A Yakama Nation 04-15-91 – – – – – – – –11N-18E-20R02B Yakama Nation 04-15-91 – – – – – – – –11N-17E-23D02 Yakama Nation 03-06-91 – – – – – – – –11N-16E-23B02 Yakama Nation 03-06-91 – – – – – – – –
96 Hydrogeologic Framework of the Yakima River Basin Aquifer System, Washington Well No. Collection agency Date Hydrogeo- logic unit Land-surface altitude (feet above NGVD 29) Hole depth (ft) Well depth (ft) Tempe- rature

(oC)

Specific

conductance

(μS/cm)

pH

Dissolved

oxygen

(mg/L)

Total 

dissolved

solids

Turbidity

(NTU)

Carbonate

(mg/L)

Bicarbonate

(mg/L)

10N-21E-19P01 Yakama Nation 02-28-91 UNCON 705 52 47 16.1 258 7.4 0.8 100 0.2 <1.0 32.0

10N-21E-28F01 Yakama Nation 02-28-91 UNCON 735 57 52 13.8 349 7.0 5.4 106 .2 <1.0 34.0

10N-18E-09N04 Yakama Nation 04-16-91 UNCON 830 94 84 14.7 536 7.3 2.2 388 2.5 <1.0 351

10N-17E-05L Yakama Nation 03-06-91 UNCON 970 59 54.5 12.4 170 6.6 8.7 202 .3 <1.0 94.0

10N-17E-17N01 Yakama Nation 03-06-91 UNCON 1,055 48 46.5 12.1 124 6.8 9.1 150 .2 <1.0 70.0

12N-19E-30P01 Yakama Nation 04-16-91 CN 935 160 156 14.0 218 7.4 2.6 216 3.6 <1.0 155

11N-19E-10Q01 Yakama Nation 12-06-90 CN 855 765 635 18.2 119 8.1 2.4 190 .3 <1.0 63.0

11N-19E-34B-9B Yakama Nation 04-10-91 CN 815 404 389 16.1 98 8.4 4.4 93.0 1.5 <1.0 59.011N-18E-03D Yakama Nation 03-26-91 CN 975 158 151 16.4 205 7.5 <.1 138 .3 <1.0 107

11N-18E-13N01 Yakama Nation 04-15-91 CN 860 127 96 13.3 390 7.3 6.0 360 7.8 <1.0 19311N-17E-02L2E Yakama Nation 11-08-90 CN 1,060 270 200 17.9 268 7.3 6.3 152 .2 <1.0 182

11N-17E-16R02 Yakama Nation 09-18-90 CN 963 200 195 14.1 431 7.4 6.8 362 .2 <1.0 20111N-17E-30D01 Yakama Nation 04-10-91 CN 1,100 302 290 16.9 218 7.1 4.8 178 19 <1.0 12211N-16E-21J Yakama Nation 04-16-91 CN 1,320 345 264 17.4 175 7.9 1.1 172 7.8 <1.0 102

10N-21E-32K02 Yakama Nation 12-06-90 CN 700 174 166 16.5 300 8.1 <.1 280 .3 <1.0 183

10N-20E-04L01 Yakama Nation 04-15-91 CN 764 1,022 809 22.2 214 7.6 .2 247 .3 <1.0 143

10N-19E-30Q01 Yakama Nation 09-12-90 CN 803 715 535 23.0 377 7.2 2.1 286 .5 <1.0 237

10N-19E-34K01 Yakama Nation 12-06-90 CN 850 219 212 16.2 427 7.4 3.9 233 .5 <1.0 287

10N-18E-04A03 Yakama Nation 04-10-91 CN 810 150 135 15.3 441 7.4 <.1 298 3.8 <1.0 281

10N-18E-04A07 Yakama Nation 04-12-91 CN 810 267 257 16.2 475 7.4 <.1 289 5.6 <1.0 310

10N-18E-09N03 Yakama Nation 04-16-91 CN 830 310 297 16.9 427 7.4 .6 334 .4 <1.0 268

10N-18E-25E01 Yakama Nation 04-16-91 CN 780 150 102 12.5 341 7.8 1.3 230 .4 <1.0 210

10N-17E-05E04 Yakama Nation 03-06-91 CN 960 395 300 12.9 165 7.6 <.1 220 1.0 <1.0 100

10N-17E-21A01 Yakama Nation 03-26-91 CN-SM 985 220 198 12.5 163 7.5 <.1 110 .3 <1.0 99.0

12N-18E-26C01 Yakama Nation 04-16-91 SM 1,140 425 213 25.0 170 7.9 < .1 210 .2 <1.0 178

12N-18E-27N02D1 Yakama Nation 09-30-90 SM-WN 1,120 1,009 690 27.1 287 7.8 – 213 2.2 <1.0 162

11N-21E-16P01 Yakama Nation 04-10-91 SM-WN 1,300 1,402 700 29.4 294 8.7 .1 244 1.3 8.4 141

11N-18E-26M03 Yakama Nation 04-15-91 SM-WN 835 1,471 1,270 28.6 348 7.4 < .1 378 .3 <1.0 223

11N-17E-02P01 Yakama Nation 03-06-91 WN 1,100 1,000 870 26.2 269 7.8 -1.3 229 1.0 <1.0 168

11N-17E-21C01 Yakama Nation 03-06-91 SM 980 640 571 19.4 156 7.8 5.2 246 1.4 <1.0 21111N-16E-09P01 Yakama Nation 03-06-91 WN 1,480 185 143 15.4 217 7.0 5.2 209 1.4 <1.0 121

Table B1. Hydrochemical data from groundwater samples, Yakima River basin aquifer system, Washington.—Continued
Appendix B

97

Well No. Collection

agency

Date Alkalinity (mg/L) Potassium (mg/L) Manga- nese (mg/L) Magne- sium (mg/L) Calcium (mg/L) Boron (mg/L) Phosphate (dissolved) (mg/L) Total phos- phorus (mg/L) Nitrite (mg/L) Nitrite + nitrate as N (mg/L) Ammonia as N (mg/L) Sulphate (mg/L)

10N-21E-19P01 Yakama Nation 02-28-91 26.0 6.00 0.11 5.60 17.0 <0.1 <0.05 <0.05 <0.002 <0.05 <0.07 0.3310N-21E-28F01 Yakama Nation 02-28-91 28.0 3.00 <.01 14.0 35.0 <.1 <.05 .06 <.002 6.10 <.07 15.010N-18E-09N04 Yakama Nation 04-16-91 288 6.00 .12 23.0 47.0 .1 .07 .13 <.002 <.05 .56 5.6010N-17E-05L Yakama Nation 03-06-91 77.0 3.00 <.01 6.90 14.0 <.1 .08 .07 <.002 .70 <.07 4.5010N-17E-17N01 Yakama Nation 03-06-91 57.0 2.00 <.01 5.40 10.0 <.1 <.05 .05 <.002 .60 <.07 2.9012N-19E-30P01 Yakama Nation 04-16-91 127 5.00 .35 17.0 39.0 <.1 <.05 <.05 <.002 <.05 <.07 53.5

11N-19E-10Q01 Yakama Nation 12-06-90 52.0 2.00 <.01 1.10 10.0 <.1 <.05 <.05 <.002 .07 <.07 1.92

11N-19E-34B-9B Yakama Nation 04-10-91 48.0 1.00 .01 0.59 9.90 <.1 <.05 .06 <.002 .08 .49 1.96

11N-18E-03D Yakama Nation 03-26-91 88.0 4.00 .14 5.70 16.0 <.1 <.05 <.05 <.002 <.05 <.07 10.7

11N-18E-13N01 Yakama Nation 04-15-91 158 4.00 .04 10.0 37.0 <.1 .06 .06 <.002 3.70 <.07 22.3

11N-17E-02L2E* Yakama Nation 11-08-90 149 4.00 <.01 11.0 24.0 <.1 .05 .06 <.002 <.05 <.07 8.50

11N-17E-16R02 Yakama Nation 09-18-90 165 2.00 <.01 16.0 35.0 <.1 <.05 <.05 <.002 4.90 <.07 22.5

11N-17E-30D01 Yakama Nation 04-10-91 100 3.00 .05 9.70 17.0 <.1 .28 .38 <.002 .50 <.07 7.40

11N-16E-21J Yakama Nation 04-16-91 84.0 4.00 .02 6.10 14.0 <.1 <.05 .05 <.002 .50 <.07 5.30

10N-21E-32K02 Yakama Nation 12-06-90 150 9.00 .08 3.90 13.0 <.1 <.05 <.05 <.002 <.05 <.07 <.25

10N-20E-04L01 Yakama Nation 04-15-91 117 4.70 .12 5.20 13.0 <.1 <.05 <.05 <.002 <.05 <.07 <.25

10N-19E-30Q01 Yakama Nation 09-12-90 194 6.00 .31 14.0 26.0 <.1 <.05 .06 <.002 <.05 <.07 .3610N-19E-34K01 Yakama Nation 12-06-90 235 2.00 <.01 16.0 43.0 <.1 <.05 <.05 <.002 .10 <.07 8.9010N-18E-04A03 Yakama Nation 04-10-91 230 5.00 .21 14.0 37.0 .1 <.05 <.05 <.002 <.05 <.07 .5710N-18E-04A07 Yakama Nation 04-12-91 254 5.00 .15 16.0 42.0 .1 <.05 <.05 <.002 <.05 <.07 <.25

10N-18E-09N03 Yakama Nation 04-16-91 220 5.00 .04 12.0 18.0 <.1 <.05 <.05 <.002 <.05 <.07 <.25

10N-18E-25E01 Yakama Nation 04-16-91 172 4.00 .12 15.0 30.0 <.1 .32 .30 <.002 <.05 .42 <.25

10N-17E-05E04 Yakama Nation 03-06-91 82.0 3.00 <.01 6.90 13.0 <.1 .11 .09 <.002 .09 <.07 2.12

10N-17E-21A01 Yakama Nation 03-26-91 81.0 1.00 .13 7.10 14.0 <.1 .09 .09 <.002 <.05 <.07 1.75

12N-18E-26C01 Yakama Nation 04-16-91 146 6.00 .04 8.50 17.0 <.1 <.05 <.05 <.002 <.05 <.07 <.25

12N-18E-27N02D1 Yakama Nation 09-30-90 133 5.00 .03 8.90 18.0 <.1 <.05 <.05 <.002 <.05 <.07 <.25

11N-21E-16P01 Yakama Nation 04-10-91 138 6.00 <.01 0.16 1.70 <.1 <.05 <.05 <.002 – <.07 –11N-18E-26M03 Yakama Nation 04-15-91 183 8.00 .10 11.0 21.0 .1 <.05 .50 <.002 <.05 <.07 <.25

11N-17E-02P01 Yakama Nation 03-06-91 138 5.00 .04 8.30 17.0 <.1 <.05 <.05 <.002 <.05 <.07 <.25

11N-17E-21C01 Yakama Nation 03-06-91 173 4.00 .07 10.0 18.0 <.1 <.05 <.05 <.002 <.05 <.07 <.25

11N-16E-09P01 Yakama Nation 03-06-91 99.0 4.00 <.01 11.0 15.0 <.1 .06 .11 <.002 1.03 <.07 5.01

Table B1. Hydrochemical data from groundwater samples, Yakima River basin aquifer system, Washington.—Continued
98 Hydrogeologic Framework of the Yakima River Basin Aquifer System, Washington Well No. Collection agency Date Chloride (mg/L) Sodium (mg/L) SiO2 (mg/L) Fluoride (mg/L) Dissolved organic carbon (mg/L)

δ18O

(per mil)

δD

(per mil)

Tritium

(TU)

14C DIC

(PMC)

δ13C DIC

(per mil)

Hydrogen

sulfide

(mg/L)

Oxidation 

reduction 

potential

(millivolts)

10N-21E-19P01 Yakama Nation 02-28-91 3.40 28.0 66.0 0.50 0.15 -17.1 -131 1.40 – – – –

10N-21E-28F01 Yakama Nation 02-28-91 5.60 12.0 33.0 <.20 .34 -14.2 -104 18.1 – – – –

10N-18E-09N04 Yakama Nation 04-16-91 7.30 33.0 75.0 .60 1.5 -15.5 -114 2.50 – – – –

10N-17E-05L Yakama Nation 03-06-91 1.80 8.10 46.0 <.20 .40 -15.1 -111 9.30 – – – –10N-17E-17N01 Yakama Nation 03-06-91 1.00 5.00 38.0 .20 <.10 -15.3 -111 10.8 – – – –

12N-19E-30P01 Yakama Nation 04-16-91 17.6 20.0 48.0 .20 .75 -14.7 -109 2.60 85.6 -13.6 – –

11N-19E-10Q01 Yakama Nation 12-06-90 1.10 11.0 36.0 .20 .34 -15.1 -111 .64 – -13.0 – –

11N-19E-34B-9B Yakama Nation 04-10-91 1.00 9.00 23.0 <.20 <.10 -15.0 -108 <.1 – – – –

11N-18E-03D Yakama Nation 03-26-91 2.80 16.0 63.0 .30 <.10 -17.7 -136 .60 – – – –

11N-18E-13N01 Yakama Nation 04-15-91 7.90 23.0 36.0 <.20 .70 -14.5 -106 18.9 – – – –

11N-17E-02L2E* Yakama Nation 11-08-90 3.40 15.0 71.0 .40 .05 -16.2 -127 <.1 52.4 -14.5 – –

11N-17E-16R02 Yakama Nation 09-18-90 17.5 26.0 52.0 1.20 1.0 -14.2 -102 10.0 83.8 -13.0 – –

11N-17E-30D01 Yakama Nation 04-10-91 3.40 12.0 56.0 .30 .20 -15.0 -120 <.1 – – – –

11N-16E-21J Yakama Nation 04-16-91 2.00 9.50 35.0 .30 <.10 -15.7 -123 <.1 36.4 -14.3 – –

10N-21E-32K02 Yakama Nation 12-06-90 4.40 39.0 56.0 .90 .67 -17.2 -132 <.1 26.4 -12.4 – –

10N-20E-04L01 Yakama Nation 04-15-91 2.50 21.0 65.0 .60 .31 -16.7 -127 .92 17.1 -10.0 – –

10N-19E-30Q01 Yakama Nation 09-12-90 4.30 29.0 74.0 .60 .44 -17.8 -137 <.1 5.38 -7.80 – –

10N-19E-34K01 Yakama Nation 12-06-90 3.00 19.0 43.0 <.20 .28 -15.8 -120 <.1 81.5 -13.8 – –

10N-18E-04A03 Yakama Nation 04-10-91 4.20 35.0 57.0 .60 .80 -18.6 -138 1.40 – -- – –

10N-18E-04A07 Yakama Nation 04-12-91 4.90 34.0 65.0 .60 .30 -17.8 -134 <.1 4.24 -7.10 – –

10N-18E-09N03 Yakama Nation 04-16-91 5.20 55.0 79.0 .80 1.1 -17.5 -131 <.1 – – – –

10N-18E-25E01 Yakama Nation 04-16-91 3.80 18.0 52.0 .40 .70 -16.1 -120 1.00 – – – –

10N-17E-05E04 Yakama Nation 03-06-91 1.09 8.60 51.0 .20 <.10 -15.8 -120 <.1 47.2 -14.6 – –

10N-17E-21A01 Yakama Nation 03-26-91 1.33 9.00 62.0 .30 <.10 -16.0 -121 <.1 – – – –

12N-18E-26C01 Yakama Nation 04-16-91 9.50 32.0 59.0 .90 <.10 -17.2 -133 <.1 11.5 -8.40 – –

12N-18E-27N02D1 Yakama Nation 09-30-90 5.60 22.0 60.0 .70 3.0 -17.2 -135 <.1 10.8 -9.60 – –

11N-21E-16P01 Yakama Nation 04-10-91 – 58.0 49.0 – 4.0 -18.8 -146 <.1 3.39 -4.50 – –

11N-18E-26M03 Yakama Nation 04-15-91 4.60 32.0 81.0 .90 .36 -18.3 -141 <.1 6.71 -9.60 – –

11N-17E-02P01 Yakama Nation 03-06-91 5.22 29.0 68.0 .80 .43 -17.1 -135 <.1 11.0 -12.6 – –

11N-17E-21C01 Yakama Nation 03-06-91 4.31 25.0 70.0 .70 .48 -17.1 -135 <.1 16.9 -13.1 – –

11N-16E-09P01 Yakama Nation 03-06-91 2.26 11.0 60.0 .30 .30 -15.8 -123 1.50 83.4 -14.0 – –

Table B1. Hydrochemical data from groundwater samples, Yakima River basin aquifer system, Washington.—Continued
Appendix B

99

Well No. Collection

agency

Date Nitrogen (mg/L) Argon (ccSTP/g) Neon (ccSTP/g) Hellium (ccSTP/g) Krypton (ccSTP/g) Xenon (ccSTP/g) Methane (mg/L) δ13C-CH4 (per mil)

10N-21E-19P01 Yakama Nation 02-28-91 – – – – – – – –10N-21E-28F01 Yakama Nation 02-28-91 – – – – – – – –10N-18E-09N04 Yakama Nation 04-16-91 – – – – – – – –10N-17E-05L Yakama Nation 03-06-91 – – – – – – – –10N-17E-17N01 Yakama Nation 03-06-91 – – – – – – – –12N-19E-30P01 Yakama Nation 04-16-91 – – – – – – – –11N-19E-10Q01 Yakama Nation 12-06-90 – – – – – – – –11N-19E-34B-9B Yakama Nation 04-10-91 – – – – – – – –11N-18E-03D Yakama Nation 03-26-91 – – – – – – – –11N-18E-13N01 Yakama Nation 04-15-91 – – – – – – – –

11N-17E-02L2E* Yakama Nation 11-08-90 – – – – – – – –11N-17E-16R02 Yakama Nation 09-18-90 – – – – – – – –11N-17E-30D01 Yakama Nation 04-10-91 – – – – – – – –11N-16E-21J Yakama Nation 04-16-91 – – – – – – – –10N-21E-32K02 Yakama Nation 12-06-90 – – – – – – – –10N-20E-04L01 Yakama Nation 04-15-91 – – – – – – – –10N-19E-30Q01 Yakama Nation 09-12-90 – – – – – – – –10N-19E-34K01 Yakama Nation 12-06-90 – – – – – – – –10N-18E-04A03 Yakama Nation 04-10-91 – – – – – – – –10N-18E-04A07 Yakama Nation 04-12-91 – – – – – – – –10N-18E-09N03 Yakama Nation 04-16-91 – – – – – – – –10N-18E-25E01 Yakama Nation 04-16-91 – – – – – – – –

10N-17E-05E04 Yakama Nation 03-06-91 – – – – – – – –10N-17E-21A01 Yakama Nation 03-26-91 – – – – – – – –12N-18E-26C01 Yakama Nation 04-16-91 – – – – – – – –12N-18E-27N02D1 Yakama Nation 09-30-90 – – – – – – – –11N-21E-16P01 Yakama Nation 04-10-91 – – – – – – – –11N-18E-26M03 Yakama Nation 04-15-91 – – – – – – – –11N-17E-02P01 Yakama Nation 03-06-91 – – – – – – – –11N-17E-21C01 Yakama Nation 03-06-91 – – – – – – – –11N-16E-09P01 Yakama Nation 03-06-91 – – – – – – – –

Table B1. Hydrochemical data from groundwater samples, Yakima River basin aquifer system, Washington.—Continued
100 Hydrogeologic Framework of the Yakima River Basin Aquifer System, Washington Well No. Collection agency Date Hydrogeo- logic unit Land-surface altitude (feet above NGVD 29) Hole depth (ft) Well depth (ft) Tempe- rature

(oC)

Specific

conductance

(μS/cm)

pH

Dissolved

oxygen

(mg/L)

Total 

dissolved

solids

Turbidity

(NTU)

Carbonate

(mg/L)

Bicarbonate

(mg/L)

11N-16E-28F02 Yakama Nation 09-18-90 WN 1,280 180 135 14.5 174 7.2 5.0 97.0 1.2 <1.0 109

11N-16E-34K03 Yakama Nation 09-18-90 GR 1,200 429 409 22.3 411 6.2 < .1 223 12 <1.0 270

10N-21E-03H01 Yakama Nation 04-16-91 SM 910 775 724 23.0 249 7.8 7.0 239 .3 <1.0 231

10N-21E-21J01 Yakama Nation 12-06-90 SM 740 554 535 22.5 314 7.9 < .1 249 .3 <1.0 184

10N-17E-06J Yakama Nation 04-15-91 GR 1,306 1,306 1,072 20.0 525 6.8 .8 518 13 <1.0 376

10N-17E-08N03 Yakama Nation 09-12-90 WN 1,020 288 285 14.3 135 7.4 8.8 109 2.0 <1.0 90.0

10N-17E-26J01 Yakama Nation 09-12-90 GR 1,000 1,000 956 24.4 391 7.4 4.6 288 .2 <1.0 250

Table B1. Hydrochemical data from groundwater samples, Yakima River basin aquifer system, Washington.—Continued

Well No. Collection

agency

Date Alkalinity (mg/L) Potassium (mg/L) Manga- nese (mg/L) Magne- sium (mg/L) Calcium (mg/L) Boron (mg/L) Phosphate (dissolved) (mg/L) Total phos- phorus (mg/L) Nitrite (mg/L) Nitrite + nitrate as N (mg/L) Ammonia as N (mg/L) Sulphate (mg/L)

11N-16E-28F02 Yakama Nation 09-18-90 89.0 3.00 <0.01 8.30 14.0 <0.1 0.05 0.05 <0.002 .46 <0.07 2.4011N-16E-34K03 Yakama Nation 09-18-90 221 6.00 .07 16.0 21.0 <.1 <.05 <.05 <.002 <0.05 <.07 <.25

10N-21E-03H01 Yakama Nation 04-16-91 189 7.70 .07 8.40 36.0 <.1 <.05 <.05 <.002 <.05 <.07 2.6210N-21E-21J01 Yakama Nation 12-06-90 151 6.40 .06 5.30 24.0 <.1 <.05 <.05 <.002 <.05 <.07 <.25

10N-17E-06J Yakama Nation 04-15-91 308 7.00 .08 29.0 36.0 .1 <.05 <.05 <.002 <.05 <.07 <.25

10N-17E-08N03 Yakama Nation 09-12-90 74.0 3.00 <.01 6.70 10.0 <.1 .09 .13 <.002 .11 <.07 .88

10N-17E-26J01 Yakama Nation 09-12-90 205 6.00 .02 16.0 22.0 <.1 <.05 <.05 <.002 <.05 <.07 <.25
Appendix B

101

Well No. Collection

agency

Date Nitrogen (mg/L) Argon (ccSTP/g) Neon (ccSTP/g) Hellium (ccSTP/g) Krypton (ccSTP/g) Xenon (ccSTP/g) Methane (mg/L) δ13C-CH4 (per mil)

11N-16E-28F02 Yakama Nation 09-18-90 – – – – – – – –11N-16E-34K03 Yakama Nation 09-18-90 – – – – – – – –10N-21E-03H01 Yakama Nation 04-16-91 – – – – – – – –10N-21E-21J01 Yakama Nation 12-06-90 – – – – – – – –10N-17E-06J Yakama Nation 04-15-91 – – – – – – – –10N-17E-08N03 Yakama Nation 09-12-90 – – – – – – – –10N-17E-26J01 Yakama Nation 09-12-90 – – – – – – – –

Table B1. Hydrochemical data from groundwater samples, Yakima River basin aquifer system, Washington.—Continued

Well No. Collection

agency

Date Chloride (mg/L) Sodium (mg/L) SiO2 (mg/L) Fluoride (mg/L)

Dissolved 

organic 

carbon

(mg/L)

δ18O

(per mil)

δD

(per mil)

Tritium

(TU)

14C DIC

(PMC)

δ13C DIC

(per mil)

Hydrogen

sulfide

(mg/L)

Oxidation 

reduction 

potential

(millivolts)

11N-16E-28F02 Yakama Nation 09-18-90 1.26 7.30 47.0 0.20 0.18 -15.9 -122 -0.70 86.3 -12.7 – –

11N-16E-34K03 Yakama Nation 09-18-90 3.26 40.0 99.0 .40 .27 -15.8 -122 -.70 13.0 -7.30 – –

10N-21E-03H01 Yakama Nation 04-16-91 4.70 25.0 37.0 .40 <.10 -19.0 -147 -.70 6.95 -13.1 – –10N-21E-21J01 Yakama Nation 12-06-90 2.70 29.0 39.0 .40 .45 -19.2 -150 -.62 9.72 -13.1 – –

10N-17E-06J Yakama Nation 04-15-91 7.10 41.0 90.0 .60 .41 -16.9 -128 -.73 6.01 -6.20 – –10N-17E-08N03 Yakama Nation 09-12-90 .70 5.50 45.0 .20 <.10 -15.8 -115 -.90 -- -13.3 – –

10N-17E-26J01 Yakama Nation 09-12-90 4.10 36.0 83.0 .90 1.0 -17.0 -132 -.70 5.48 -5.70 – –
102 Hydrogeologic Framework of the Yakima River Basin Aquifer System, Washington

Appendix C. Methods Used to Estimate Groundwater Recharge for the Area 

Outside the Yakima River Basin in the Extended Study Area

Groundwater recharge was estimated for nearly the entire 

aquifer system within the Yakima River basin as part of this 

study (Vaccaro and Olsen, 2007a). Estimates of recharge were 

also needed for the area outside the boundary of the basin that 

is within the extended study area and for about 108 mi2 within 

the basin where recharge was not estimated. These areas 

are scheduled to be included in a regional groundwater flow 

model being constructed as part of this study. Two methods 

were used to estimate mean annual and monthly recharge for 

a base period of water years 1960–2001. One method was 

used for selected areas where estimated mean annual recharge 

values for the period 1956–77 were available. These values 

were estimated by Bauer and Vaccaro (1990) using the Deep 

Percolation Model (DPM). The other method, using mean 

annual precipitation (MAP) as a predictor of mean annual 

recharge, was used for the remaining area.

Recharge estimates for the two areas needed to be 

referenced to approximately the same base period. Estimated 

recharge values for one of the modeled areas of Vaccaro and 

Olsen (2007a) were selected as the base-period (1960–2001) 

reference values based on the area’s proximity, mean annual 

recharge values, and land-use/land-cover. The modeled area, 

called Cold-Dry, included 321.3 mi2 and had a mean annual 

recharge estimate of 0.44 in. for predevelopment land-use/

land-cover conditions for the period 1950–2003 (Vaccaro 

and Olsen, 2007a). The ratio of mean annual recharge for the 

period 1960–2001 to that for the period 1956–1977 for ColdDry was calculated as 0.934; the ratio is less than 1.0 because 

of the general trend of declining precipitation starting in 1977 

(Vaccaro, 1995, 2002). This is the adjustment factor used to 

multiply the mean annual estimates of Bauer and Vaccaro 

(1990) to obtain consistent, mean annual base-period values. 

The precipitation-derived mean annual recharge values were 

multiplied by an adjustment factor of 0.858 to make them 

consistent with the 1960–2001 base period; the adjustment 

factor was the ratio of Cold-Dry mean annual recharge for 

1960–2001 to that for 1971–2000, which is the climate normal 

for the MAP.

Next, for each water year, the ratio of the annual value 

to the 1960–2001 mean annual value for Cold-Dry was 

calculated. This ratio is the factor (F) used to adjust the baseperiod referenced mean annual values of Bauer and Vaccaro 

(1990) to water year values. Last, the monthly percent of 

annual recharge for water years 1960–2001 was calculated 

for Cold-Dry. These 42 water years of monthly factors are 

used to estimate the monthly values using the adjusted mean 

annual values to water year values. For example, to estimate 

recharge for month 1 (October) of water year 1960 for a cell in 

a modeled area:

Mon1, 1960 = ((BVMA)*0.934)*F60)*Mon%Ann ,

where

Mon1, 1960 is estimated recharge for month 1 of 1960;

BVMA is mean annual recharge value for a model

cell of Bauer and Vaccaro (1990);

F60 is the ratio of Cold-Dry annual recharge

 for 1960 to its 1960-2001 mean annual

value, and

Mon%Ann is month 1 percent of annual for 1960 for

Cold-Dry.

(1)

Model-calculated mean annual recharge values for three 

modeled areas (zones 4, 8, and 14 of Bauer and Vaccaro 

[1990]) were selected for applying the first method. These 

zones covered 682 mi2 and included 1,840 cells that had an 

approximate area of 0.375 mi2. Of this total area, 385 mi2 

already had estimates of recharge available from Vaccaro 

and Olsen (2007a), so that recharge was needed only for 

the remaining 297 mi2. A 500 ft raster grid was overlaid 

on the combined three areas, and an association between 

a raster grid cell outside of the areas modeled by Vaccaro 

and Olsen (2007a) and a cell in one of the three models was 

established. There were a total of 48,838 500-ft grid cells 

and there were 694 unique DPM cells for the grid cells. The 

spatial distribution of the mean annual recharge values were 

preserved because the DPM model cells of Bauer and Vaccaro 

(1990) were much larger than the raster grid cell size. The 

mean annual value for each of the 694 unique cells was then 

multiplied by 0.934 in order to obtain a spatial distribution 

of mean annual values adjusted to the base period. This 

method of relating recharge values (both monthly and annual) 

to a raster grid is similar to that used by Vaccaro and Olsen 

(2007b).
Appendix C 103

To obtain monthly values from the adjusted mean 

annual values, the values were first multiplied by the factor F, 

described above (for example, F60), for each water year. The 

resulting 42 values were then multiplied by the 12 Mon%Ann 

values for each month of a water year. These calculations 

yielded one ASCII file of estimated monthly recharge that 

is spatially related using the raster grid with its unique 

identification numbers.

Model-calculated estimates of recharge were not 

available for the remaining 511 mi2. For this area, a 

polynomial relation between mean annual recharge and MAP 

of Bauer and Vaccaro (1990) was used. MAP was for the 

climate normal of 1971–2000, and is a raster grid with an 

800-m size cell (Spatial Climate Analysis Service–Oregon 

State University, 2006). Mean annual recharge was calculated 

using the relation of Bauer and Vaccaro (1990) for each MAP 

cell in this area. These values were multiplied by the 0.858 

factor to adjust them to the 1960–2001 base period. The 

mean annual recharge values were then made into an ASCII 

file that had the 800-m raster grid identification number and 

an associated mean annual recharge value. Using the same 

methods and information described above, one ASCII file 

containing monthly values for each water year was then 

generated.

The 500-ft raster grid described in Vaccaro and Olsen 

(2007b) was then overlaid on the two raster grids described 

above in order to assign a unique identifier to the grid. Thus, a 

single 500 ft raster grid was developed for the extended study 

area that contains unique identification numbers that can be 

directly related to ASCII files containing monthly recharge 

estimates.
104 Hydrogeologic Framework of the Yakima River Basin Aquifer System, Washington

This page intentionally left blank.
Appendix D 105

Appendix D. Estimation of Mean Annual Values and Development of TimeSeries of Monthly Values for Surface-Water Diversions, Yakima River Basin, 

Washington

Monthly values for 65 surface-water diversions within 

the Yakima River basin were obtained from the Bureau of 

Reclamation (R. Larson, written commun., 2007 and R. 

Sonnichsen, written commun., 2007; and Hydromet— http://

www.usbr.gov/pn/hydromet/yakima/yakwebarcread.html). 

Monthly observed or estimated values for the base period of 

water years 1960–2001 were available for Kittitas, Sunnyside, 

Tieton, Chandler, New Reservation, Kennewick, Roza, 

Naches-Selah, South Naches, and Westside canals. For most 

of the other 54 diversions, monthly observed or estimated 

information was available only through water year 1999 for 

the information provided by Larson and through 2001 for 

the information provided by Sonnichsen. However, the latter 

information started in water year 1981. In order to extend 

the records of Larson through 2001, diversions in 2000 were 

assumed to be the same as those in 1998. Both 1998 and 2000 

had nearly the same Total Water Supply Available (forecasted 

water supply for the irrigation season) and the storage control 

date was the same. For diversions in 2001, it was assumed that 

those diversions were the same as those in 1994, which had 

the same April 1 prorating percent of 37 (junior surface-water 

users obtained only 37 percent of their entitlement). As an 

indication of the accuracy of these estimates, for canals with 

records through 2001 the mean annual diversion in 1994 was 

as much as 12 percent smaller and as much as 8 percent higher 

than 2001. In addition, monthly values for the two diversions 

of the Cascade Irrigation District (CID) were only through 

1991 and 1994. The remaining monthly values were provided 

by CID (Cascade Irrigation District, written commun., 2007).

The mean annual values were then calculated for 49 

canals (a subset of the 54 described above) common to both 

Reclamation data sets. The values were compared to each 

other and to their percent of the entitlement. It was determined 

that for 28 diversions the monthly values may have been 

estimated as either too large or too small. Based on a ratio of 

mean annual values from the two sources, the monthly values 

for 1960–2001 were modified. This resulted in a net increase 

of 68 ft3/s or about 10 percent of the total mean annual 

diversion for the 49 canals. The 68 ft3/s is only about 1 percent 

of the total for the 65 diversions. The resulting total mean 

annual value for the 65 diversions is about 86 percent of the 

total entitlement for these canals. 

Most of the remaining surface-water diversion quantities 

were obtained from a file provided by WaDOE (B. Johnson, 

Washington State Department of Ecology, written commun., 

2007). For each diversion, the file contained its maximum 

allowable instantaneous rate, annual entitlement, and in 

most cases, a name and location. The information provided 

by WaDOE contained no measured or estimated monthly 

or annual diversion quantities. First, diversions identified 

as springs or spring-fed creeks were not included in this 

analysis. However, these springs are presented on a map of 

the springs in the basin in this report. Next, diversions with 

small annual entitlements (generally less than 5 acre-ft) 

and diversions without location information also were not 

included; together these accounted for about 6 percent of the 

total annual entitlement of all of the diversions in the file. 

Last, diversions that were part of the above 65 were excluded. 

Except for the Yakima and Naches Rivers, diversions were 

then generally aggregated to one or several locations for each 

stream based on the locations of the largest entitlements. 

This aggregation resulted in 70 points of withdrawals. The 

full annual entitlement value was used as the estimate of 

the mean annual diversion (B. Johnson, Washington State 

Department of Ecology, written commun., 2007), and thus, 

was assumed to be constant for every year. Information for 

eight other diversions in the Toppenish basin was obtained 

from the Yakama Nation (D. Lind, Yakama Nation, written 

commun., 2007). The information included location and the 

estimated mean annual and maximum diversion quantities. 

Similar to a diversion in the Ahtanum subbasin, seven of 

the eight diversions are shut off in the summer to maintain 

instream flows (D. Lind, Yakama Nation, written commun., 

2007). Based on the average of the ratio of the mean monthly 

to the mean annual quantities for the 65 diversions, monthly 

multiplying factors were calculated for distributing the final 78 

mean annual values over the April through October irrigation 

season. These factors ranged from 0.68 in October to 2.17 in 

July. The monthly estimates for these 78 points and the 65 

other diversions are needed for other parts of this study and 

provide a comparison with the groundwater pumpage in the 

basin. 
106 Hydrogeologic Framework of the Yakima River Basin Aquifer System, Washington

This page intentionally left blank.
Publishing support provided by the U.S. Geological Survey

Publishing Network, Tacoma Publishing Service Center

For more information concerning the research in this report, contact the

Director, Washington Water Science Center

U.S. Geological Survey, 934 Broadway — Suite 300

Tacoma, Washington 98402

http://wa.water.usgs.gov
2

Report Title

Printed on recycled paper

Vaccaro and others—Hydrogeologic Framework of the Yakima River Basin Aquifer System, Washington— Scientific Investigations Report 2009–5152