U.S. Department of the Interior

U.S. Geological Survey

Ground - Water Hydrology of the

Upper Deschutes Basin, Oregon

BY MARSHALL W. GANNETT, KENNETH E. LITE JR.,

DAVID S. MORGAN, AND CHARLES A. COLLINS

Water-Resources Investigations Report 00–4162

Prepared in cooperation with Oregon Water Resources Department;

cities of Bend, Redmond, and Sisters; Deschutes and Jefferson Counties;

The Confederated Tribes of the Warm Springs Reservation of Oregon;

and U.S. Environmental Protection Agency

Portland, Oregon: 2001
U. S. DEPARTMENT OF THE INTERIOR

BRUCE BABBITT, Secretary

U.S. GEOLOGICAL SURVEY

CHARLES G. GROAT, Director

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

is for descriptive purposes only and does not imply

endorsement by the U.S. Government.

For additional information contact: Copies of this report can be

purchased from:

District Chief

U.S. Geological Survey USGS Information Services

10615 S.E. Cherry Blossom Drive Box 25286, Federal Center

Portland, OR 97216-3159 Denver, CO 80225-0046

E-mail: info-or@usgs.gov Telephone: 1-888-ASK-USGS

Internet: http://oregon.usgs.gov

Suggested citation:

Gannett, M.W., Lite, K.E., Jr., Morgan, D.S., and Collins, C.A., 2001, Ground-water hydrology of the upper

Deschutes Basin, Oregon: U.S. Geological Survey Water-Resources Investigations Report 00–4162, 78 p.
iii

CONTENTS

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

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

Background and Study Objectives....................................................................................................................................2

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

Study Area.........................................................................................................................................................................3

Approach...........................................................................................................................................................................6

Acknowledgments.............................................................................................................................................................8

Geologic Framework...................................................................................................................................................................8

Geologic Controls on Regional Ground-Water Flow .......................................................................................................9

Hydraulic Characteristics of Subsurface Materials.........................................................................................................13

Aquifer Tests.........................................................................................................................................................14

Well-Yield Tests ...................................................................................................................................................18

Ground-Water Recharge ...........................................................................................................................................................19

Infiltration of Precipitation..............................................................................................................................................19

Canal Leakage.................................................................................................................................................................23

On-Farm Losses ..............................................................................................................................................................27

Stream Leakage...............................................................................................................................................................28

Drainage Wells................................................................................................................................................................39

Interbasin Flow ...............................................................................................................................................................40

Ground-Water Discharge ..........................................................................................................................................................41

Ground-Water Discharge to Streams ..............................................................................................................................41

Geographic Distribution of Ground-Water Discharge to Streams........................................................................42

Temporal Variations in Ground-Water Discharge to Streams..............................................................................47

Ground-Water Discharge to Wells..................................................................................................................................53

Irrigation Wells .....................................................................................................................................................53

Public-Supply Wells .............................................................................................................................................53

Private Domestic Wells.........................................................................................................................................56

Ground-Water Discharge to Evapotranspiration.............................................................................................................58

Ground-Water Elevations and Flow Directions........................................................................................................................58

Horizontal Ground-Water Flow ......................................................................................................................................59

Vertical Ground-Water Flow ..........................................................................................................................................61

Fluctuations in Ground-Water Levels.......................................................................................................................................64

Large-Scale Water-Table Fluctuations ...........................................................................................................................64

Local-Scale Water-Table Fluctuations............................................................................................................................65

Summary and Conclusions........................................................................................................................................................73

References Cited .......................................................................................................................................................................75

FIGURES

1. – 6. Maps showing:

1. Location of the upper Deschutes Basin, Oregon, and major geographic and cultural features ..............................4

2. Location of field-located wells and land ownership in the upper Deschutes Basin, Oregon..................................5

3. Lines of equal precipitation and graphs of mean monthly precipitation for selected precipitation

stations in the upper Deschutes Basin, Oregon.......................................................................................................7

4. Generalized geology of the upper Deschutes Basin, Oregon................................................................................10

5. Distribution of transmissivity estimates derived from specific-capacity tests of field-located domestic

wells in the upper Deschutes Basin, Oregon, and the locations of aquifer tests conducted for this study ...........15

6. Deep Percolation Model grid and estimated recharge from infiltration of precipitation, 1993–95......................20

7. – 8. Graphs showing:

7. Annual mean components of the basinwide water budget, estimated using the Deep Percolation Model

for water years 1962–97........................................................................................................................................22

8. Mean monthly components of the basinwide water budget, estimated using the Deep Percolation Model

for water years 1962–97........................................................................................................................................23
iv

9. Map showing mean annual recharge from canal leakage and on-farm losses in the upper Deschutes Basin,

Oregon, 1993–95.........................................................................................................................................................24

10. Graph showing annual canal diversions and estimated annual mean canal leakage in the upper Deschutes

Basin, Oregon, 1905–97..............................................................................................................................................28

11.–12. Maps showing:

11. Location of selected stream-gaging stations in the upper Deschutes Basin, Oregon............................................32

12. Estimated gain and loss flux rates and net gains and losses for selected stream reaches in the upper

Deschutes Basin, Oregon ......................................................................................................................................37

13. Graph showing relation between monthly mean losses along the Deschutes River between Benham Falls

and Lava Island and flow at Benham Falls .................................................................................................................38

14.–15. Hydrographs showing:

14. Mean monthly flows of selected nonregulated streams in the upper Deschutes Basin, Oregon ..........................42

15. Monthly mean flow of the Metolius River near Grandview.................................................................................43

16.–17. Graphs showing:

16. Gain in flow of the lower Crooked River, Oregon, due to ground-water discharge between river

miles 27 and 7, July 1994......................................................................................................................................45

17. Gain in flow of the Deschutes River, Oregon, due to ground-water discharge between river miles

165 and 120, May 1992 and May 1994 ................................................................................................................45

18. Diagrammatic section showing the effect of geology on ground-water discharge along the Deschutes River

upstream of Pelton Dam..............................................................................................................................................46

19. Graph showing cumulative departure from normal annual mean flows of selected streams in the upper

Deschutes Basin, and cumulative departure from normal annual precipitation at Crater Lake, Oregon,

1947–91.......................................................................................................................................................................49

20. Hydrograph showing October mean flows of the Metolius River, Jefferson Creek, and Whitewater River,

upper Deschutes Basin, Oregon, 1984–97 ..................................................................................................................49

21. Graph showing approximate August mean ground-water discharge to the middle Deschutes River between

Bend and Culver, based on the difference between August mean streamflows at gages below Bend and

near Culver, 1954–97..................................................................................................................................................51

22. Hydrograph showing monthly mean flows of the Crooked River at the gage below Opal Springs,

1962–97.......................................................................................................................................................................51

23.–24. Graphs showing:

23. August mean flows of the Crooked River below Opal Springs, the Metolius River near Grandview,

and estimated annual mean leakage from irrigation canals, 1905–97 ..................................................................52

24. Estimated annual ground-water pumpage for irrigation in the upper Deschutes Basin, Oregon,

1978–97.................................................................................................................................................................54

25. Map showing estimated average annual ground-water pumpage for irrigation in the upper Deschutes Basin,

Oregon, 1993–95, aggregated by section....................................................................................................................55

26. Graph showing estimated annual ground-water pumpage for public-supply use in the upper Deschutes

Basin, Oregon, 1978–97..............................................................................................................................................56

27.–28. Maps showing:

27. Estimated average annual ground-water pumpage for public-supply use in the upper Deschutes Basin,

Oregon, 1993–95, aggregated by section..............................................................................................................57

28. Generalized lines of equal hydraulic head and ground-water flow directions in the upper Deschutes

Basin, Oregon........................................................................................................................................................60

29. Diagrammatic section southwest-northeast across the upper Deschutes Basin, Oregon, showing flow

directions and lines of equal hydraulic head...............................................................................................................62

30. Map showing generalized lines of equal hydraulic head for shallow and deep water-bearing zones in the

central part of the upper Deschutes Basin, Oregon.....................................................................................................63

31.–32. Hydrographs showing:

31. Static water levels in two long-term observation wells in the upper Deschutes Basin, Oregon, and

cumulative departure from normal annual precipitation at Crater Lake, Oregon, 1962–98.................................64

32. Variations in static water levels of selected wells at various distances from the Cascade Range,

1994–98.................................................................................................................................................................66

33. Maps showing year-to-year changes in March static water levels in observation wells in the upper

Deschutes Basin, Oregon, 1994–98 ............................................................................................................................67
v

34.–40. Hydrographs showing:

34. Static water-level variations in a shallow well and a deep well in the La Pine subbasin, Oregon .......................68

35. Relation between static water-level variations in a deep well near Bend, Oregon, and flow rate

in a nearby irrigation canal....................................................................................................................................69

36. Relation between static water-level variations in a well near Redmond, Oregon, and flow rate

in a nearby irrigation canal....................................................................................................................................69

37. Relation between static water-level variations in two wells at different distances from the

Deschutes River and stage of the river at Benham Falls.......................................................................................70

38. Relation between monthly mean discharge of Fall River and static water-level variation in a

well near Sisters, Oregon, 1962–97 ......................................................................................................................70

39. Static water level in an unused irrigation well near Lower Bridge, showing seasonal pumping

effects from nearby irrigation wells and long-term climatic effects.....................................................................72

40. Water levels in two wells near Round Butte Dam, showing the rise in ground-water elevations

caused by the filling of Lake Billy Chinook .........................................................................................................72

TABLES

1. Summary of selected aquifer tests in the upper Deschutes Basin, Oregon.................................................................16

2. Statistics for transmissivities estimated from specific-capacity data for subareas in the upper Deschutes

Basin, Oregon..............................................................................................................................................................18

3. Weather stations used for estimation of recharge from infiltration of precipitation with the

Deep Percolation Model..............................................................................................................................................21

4. Canal diversions, irrigated acreage, on-farm deliveries, and canal leakage, by major canal service area,

upper Deschutes Basin, Oregon, 1994 ........................................................................................................................27

5. Gain/loss measurements of major streams obtained from Oregon Water Resources Department seepage

runs, upper Deschutes Basin, Oregon .........................................................................................................................30

6. Station numbers, names, and mean annual flow for selected gaging stations in the upper Deschutes Basin,

Oregon.........................................................................................................................................................................33

7. Estimated stream gains and losses due to ground-water exchange, upper Deschutes Basin, Oregon ........................34

8. Statistical summaries of selected nonregulated streams in the upper Deschutes Basin, Oregon................................48

CONVERSION FACTORS AND VERTICAL DATUM

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

°F=1.8 °C+32

Sea level: In this report, “sea level” refers to the National Geodetic Vertical Datum of 1929 (NGVD of 1929) — a geodetic

datum derived from a general adjustment of the first-order level nets of both the United States and Canada, formerly called

Sea Level Datum of 1929.

Multiply By To obtain

inch (in.) 25.4 millimeter (mm)

foot (ft) 0.3048 meter (m)

mile (mi) 1.609 kilometer (km)

acre 4,047 square meter (m2)

square mile (mi2) 2.590 square kilometer (km2)

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

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

inches per year (in./yr) 0.0254 meters per year (m/yr)

feet per day (ft/d) 3.528 × 10-6 meters per second (m/s)

gallon per minute (gal/min) 6.308 × 10-5 cubic meters per second (m3/s)

square feet per day (ft2/d) 1.075 × 10-5 square meters per second (m2/s)

feet per year (ft/yr) 9.659 × 10-9 meters per second (m/s)

acre-feet per year (acre-ft/yr) 3.909 × 10-5 cubic meters per second (m3/s)

cubic feet per day per square foot (ft3/d/ft2) 3.528 × 10-6 cubic meters per second per square meter (m3/s/m2)

gallons per day (gal/d) 4.381 × 10-8 cubic meters per second (m3/s)

feet per second (ft/s) 0.3048 meter per second (m/s)
vi

LOCATION SYSTEM

The system used for locating wells, springs, and surface-water sites in this report is based on the

rectangular system for subdivision of public land. The State of Oregon is divided into townships of

36 square miles numbered according to their location relative to the east-west Willamette baseline and

a north-south Willamette meridian. The position of a township is given by its north-south “Township”

position relative to the baseline and its east-west “Range” position relative to the meridian. Each

township is divided into 36 one-square-mile (640-acre) sections numbered from 1 to 36. For example,

a well designated as 18S/11E-29AAC is located in Township 18 south, Range 11 east, section 29.

The letters following the section number correspond to the location within the section; the first letter

(A) identifies the quarter section (160 acres); the second letter (A) identifies the quarter-quarter section

(40 acres); and the third letter (C) identifies the quarter-quarter-quarter section (10 acres). Therefore,

well 29AAC is located in the SW quarter of the NE quarter of the NE quarter of section 29. When more

than one designated well occurs in the quarter-quarter-quarter section, a serial number is included.

Each well is assigned a unique 8-digit identification number known as the log-id number. The first

two digits of the log-id number indicate the county code from the Federal Information Processing

Standards (FIPS) code file for the county in which the well exists. The FIPS codes for the counties

in the study area are as follows: 13, Crook County; 17, Deschutes County; 31, Jefferson County;

and 35, Klamath County. The last 6 digits of the number correspond to the State of Oregon well-log

number (a unique number assigned by the Oregon Water Resources Department to the report filed

by the well driller).

MAPPING SOURCES:

Base map modified from U.S. Geological Survey 1:500,000 State base map,

1982, with digital data from U.S. Bureau of the Census, TIGER/Line (R), 1990,

and U.S. Geological Survey Digital Line Graphs published at 1:100,000.

Publication projection is Lambert Conformal Conic.

Standard parallels 43ο00’ and 45ο30’, central meridian –120ο30’.

1

12

13

24

25

36

2

11

14

23

26

35

3

10

15

22

27

34

4

9

16

21

28

33

5

8

17

20

29

32

6

7

18

19

30

31

T. 18 S.

T. 20 S.

R. 6 E. R. 8 E. R. 10 E. R. 12 E.

18S/11E-29AAC

A

C D

B

B A

C D

C D

29

B A

Well- and spring-location system.
1

Ground-Water Hydrology of the Upper Deschutes Basin,

Oregon

By Marshall W. Gannett, Kenneth E. Lite Jr., David S. Morgan, and Charles A. Collins

Abstract

The upper Deschutes Basin is among the

fastest growing regions in Oregon. The rapid

population growth has been accompanied by

increased demand for water. Surface streams,

however, have been administratively closed to

additional appropriation for many years, and

surface water is not generally available to support

new development. Consequently, ground water

is being relied upon to satisfy the growth in water

demand. Oregon water law requires that the

potential effects of ground-water development

on streamflow be evaluated when considering

applications for new ground-water rights. Prior

to this study, hydrologic understanding has been

insufficient to quantitatively evaluate the connection between ground water and streamflow, and

the behavior of the regional ground-water flow

system in general. This report describes the

results of a hydrologic investigation undertaken

to provide that understanding. The investigation

encompasses about 4,500 square miles of the

upper Deschutes River drainage basin.

A large proportion of the precipitation in

the upper Deschutes Basin falls in the Cascade

Range, making it the principal ground-water

recharge area for the basin. Water-balance

calculations indicate that the average annual rate

of ground-water recharge from precipitation

(1993–95) is about 3,500 ft3/s (cubic feet per

second). Water-budget calculations indicate that

in addition to recharge from precipitation, water

enters the ground-water system through interbasin

flow. Approximately 800 ft3/s flows into the

Metolius River drainage from the west and about

50 ft3/s flows into the southeastern part of the

study area from the Fort Rock Basin. East of the

Cascade Range, there is little or no ground-water

recharge from precipitation, but leaking irri

canals are a significant source of artificial

recharge north of Bend. The average annua

of canal leakage during 1994 was estimated 

about 490 ft3/s. Ground water flows from th

Cascade Range through permeable volcanic 

eastward out into the basin and then genera

northward. About one-half the ground wate

flowing from the Cascade Range discharges 

spring-fed streams along the margins of the 

including the upper Metolius River and its t

taries. The remaining ground water flows th

the subsurface, primarily through rocks of t

Deschutes Formation, and eventually discha

to streams near the confluence of the Desch

Crooked, and Metolius Rivers. Substantial

ground-water discharge occurs along the lo

2 miles of Squaw Creek, the Deschutes Riv

between Lower Bridge and Pelton Dam, the 

Crooked River between Osborne Canyon an

mouth, and in Lake Billy Chinook (a reserv

that inundates the confluence of the Deschu

Crooked, and Metolius Rivers).

The large amount of ground-water disc

in the confluence area is primarily caused b

geologic factors. North (downstream) of the

confluence area, the upper Deschutes Basin 

transected by a broad region of low-permea

rock of the John Day Formation. The Desch

River flows north across the low-permeabili

region, but the permeable Deschutes Forma

through which most of the regional ground 

flows, ends against this rampart of low-perm

ability rock. The northward-flowing ground 

discharges to the streams in this area becau

permeable strata through which it flows term

forcing the water to discharge to the surface
2

Virtually all of the regional ground water in the

upper Deschutes Basin discharges to surface

streams south of the area where the Deschutes

River enters this low-permeability terrane, at

roughly the location of Pelton Dam.

The effects of ground-water withdrawal on

streamflow cannot presently be measured because

of measurement error and the large amount of

natural variability in ground-water discharge.

The summer streamflow near Madras, which is

made up largely of ground-water discharge, is

approximately 4,000 ft3/s. Estimated consumptive

ground-water use in the basin is about 30 ft3/s,

which is well within the range of the expected

streamflow measurement error. The natural

variation in ground-water discharge upstream

of Madras due to climate cycles is on the order

of 1,000 ft3/s. This amount of natural variation

masks the effects of present ground-water use.

Even though the effects of ground-water use on

streamflow cannot be measured, geologic and

hydrologic analysis indicate that they are present.

Ground-water-level fluctuations in the

upper Deschutes Basin are driven primarily by

decadal climate cycles. Decadal water-level

fluctuations exceeding 20 ft (feet) have been

observed in wells at widespread locations near

the margin of the Cascade Range. The magnitude

of these fluctuations diminishes toward the east,

with increasing distance from the Cascade Range.

Annual water-level fluctuations of a few feet are

common in areas of leaking irrigation canals, with

larger fluctuations observed in some wells very

close to canals. Annual water-level fluctuations

of up to 3 ft due to ground-water pumping were

observed locally. No long-term water-level

declines attributable to pumping were found in

the upper Deschutes Basin.

The effects of stresses to the ground-water

system are diffused and attenuated with distance.

This phenomenon is shown by the regional

response to the end of a prolonged drought and

the shift to wetter-than-normal conditions starting

in 1996. Ground-water levels in the Cascade

Range, the locus of ground-water recharge,

stopped declining and started rising during the

winter of 1996. In contrast, water levels in t

Redmond area, 30 miles east of the Cascade

Range, did not start to rise again until late 1

or 1998. The full effects of stresses to the g

water system, including pumping, may take

several years to propagate across the basin.

Ground-water discharge fluctuations w

analyzed using stream-gage records. Groun

water discharge from springs and seeps esti

from stream-gage records shows climate-dr

decadal fluctuations following the same pat

as the water-level fluctuations. Data from 1

to 1997 show decadal-scale variations of 22 

74 percent in ground-water discharge along 

streams that have more than 100 ft3/s of gro

water inflow.

INTRODUCTION

Background and Study Objectives

The upper Deschutes Basin is presently o

the fastest growing population centers in the Sta

Oregon. The number of people in Deschutes Co

the most populous county in the basin, more tha

tripled between 1970 and 1998 (State of Oregon

1999). Approximately 140,000 people lived in t

upper Deschutes Basin as of 1998. Growth in th

region is expected to continue, and residents an

government agencies are concerned about wate

supplies for the burgeoning population and the

consequences of increased development for exi

water users. Surface-water resources in the area 

been closed by the State of Oregon to additiona

appropriation for many years. Therefore, virtua

new development in the region must rely on gro

water as a source of water. Prior to this study, v

little quantitative information was available on 

ground-water hydrology of the basin. This lack 

information made ground-water resource mana

ment decisions difficult and was generally a cau

for concern.

To fill this information void, the U.S. Geo

Survey (USGS) began a cooperative study in 19

with the Oregon Water Resources Department

(OWRD), the cities of Bend, Redmond, and Sis

Deschutes and Jefferson Counties, The Confede

Tribes of the Warm Springs Reservation of Ore

and the U.S. Environmental Protection Agency.
3

The objectives of this study were to provide a quantitative assessment of the regional ground-water system

and provide the understanding and analytical tools

for State and local government agencies, hydrologists,

and local residents to make resource management

decisions. This report is one in a series that presents

the results of the upper Deschutes Basin ground-water

study.

Purpose and Scope

The purpose of this report is to provide a

comprehensive quantitative description of regional

ground-water flow in the upper Deschutes Basin. The

report provides an analysis of the data compiled or

collected during the study, and presents a description

of the regional ground-water hydrology based on that

analysis.

The results of the study presented herein are

based on both preexisting information and new data.

Preexisting information included regional-scale maps

of geology, topography, soils, vegetation, and precipitation. In addition, streamflow data were available

for numerous sites for periods of time since the early

1900s. Data were also available from several weather

stations that operate in the study area. In addition,

surface-water diversion records were available for all

major irrigation canals. Data described above were

augmented by data from numerous reports and studies.

Hydrologic data collected for this study included

gain/loss measurements for several streams, and geologic and hydraulic-head data from about 1,500 wells

that were precisely located in the field. Geophysical,

lithologic, and hydrographic data were collected from

a subset of these wells. Wells are unevenly distributed

in the area and occur mostly in areas of privately

owned land. There are few well data from the large

tracts of public land that cover most of the study

area. Therefore, there are large regions of the Cascade

Range, Newberry Volcano, and the High Lava Plains

where subsurface hydrologic information is sparse.

This study is regional in scope. It is intended

to provide the most complete assessment possible of

the regional ground-water hydrology of the upper

Deschutes Basin given the data that were available

or that could be collected within the resources of

the project. This work is not intended to describe

details of ground-water flow at local scales; however,

it will provide a sound framework for local-scale

investigations.

Study Area

The upper Deschutes Basin study area enc

passes approximately 4,500 mi2 (square miles) 

the Deschutes River drainage basin in central O

(fig. 1). The area is drained by the Deschutes R

and its major tributaries: the Little Deschutes R

Tumalo Creek, Squaw Creek, and the Metolius 

from the west, and the Crooked River from the 

Land-surface elevation ranges from less than 1,

near Gateway in the northern part of the study a

more than 10,000 ft above sea level in the Casc

Range.

The study-area boundaries were chosen to 

cide as much as possible with natural hydrologi

boundaries across which ground-water flow can 

reasonably estimated or assumed to be negligib

The study area is bounded on the north by Jeffe

Creek, the Metolius River, the Deschutes River

Trout Creek; on the east by the generalized con

between the Deschutes Formation and the older

less permeable John Day Formation; on the sou

the drainage divides between the Deschutes Bas

the Fort Rock and Klamath Basins; and on the w

the Cascade Range crest.

The study area includes the major populat

centers in the basin, where ground-water develo

is most intense and resource management quest

are most urgent. The major communities includ

Bend, Redmond, Sisters, Madras, Prineville, an

La Pine. Principal industries in the region are

agriculture, forest products, tourism, and servic

industries.

Sixty-six percent of the 4,500 mi2 upper D

chutes Basin is publicly owned (fig. 2). Approxi

2,230 mi2 are under the jurisdiction of the U.S. 

Service, 730 mi2 are under the jurisdiction of th

Bureau of Land Management, and about 20 mi2 

under the stewardship of State or County agenc

The remaining 1,520 mi2 are in private ownersh

The highest elevations in the upper Desch

Basin are in the western and southern parts. Th

regions are covered by coniferous forests, most 

which have been managed for timber productio

The remaining parts of the basin, which are at l

elevations, are more arid and, where not cultiva

are dominated by grassland, sagebrush, and jun

Most of the non-forest-related agriculture occur

the central and northern parts of the upper Desc

Basin.
6

There are approximately 164,000 acres

(256 mi2) of irrigated agricultural land in the study

area. The largest source of irrigation water is the

Deschutes River. Most water is diverted from the

Deschutes River near Bend and distributed to areas

to the north through several hundred miles of canals.

Smaller amounts of irrigation water are diverted from

Tumalo and Squaw Creeks, the Crooked River, and

Ochoco Creek.

The climate in the Deschutes Basin is controlled

primarily by air masses that move eastward from

the Pacific Ocean, across western Oregon, and into

central Oregon. The climate is moderate with cool,

wet winters and warm, dry summers. Orographic processes result in large amounts of precipitation in the

Cascade Range in the western part of the basin, with

precipitation locally exceeding 200 in./yr (inches per

year), mostly as snow, during the winter (Taylor,

1993). Precipitation rates diminish rapidly toward the

east to less than 10 in./yr in the central part of the

basin (fig. 3). Temperatures also vary across the basin.

Records from the Oregon Climate Service show

mean daily minimum and maximum temperatures

at Santiam Pass in the Cascade Range (period of

record 1961–85) range from 21 and 34οF (degrees

Fahrenheit) in January to 43 and 73οF in July (Oregon

Climate Service, 1999). Conditions are warmer at

lower elevations in the central part of the basin. The

mean daily minimum and maximum temperatures in

Bend (period of record 1961 to 1999) range from

22 and 42οF in January to 45 and 81οF in July

(Oregon Climate Service, 1999). Climate in the

Deschutes Basin exhibits year-to-year and longerterm variability. This variability generally parallels

regional trends in the Pacific Northwest that have been

correlated with large-scale ocean-atmosphere climate

variability patterns in the Pacific Basin such as the

El Niño/Southern Oscillation (Redmond and Koch,

1991) and the Pacific Decadal Oscillation (Mantua and

others, 1997).

Approach

The approach to this study consisted of five

major elements: (1) reviewing existing geologic

and hydrologic maps and literature and conceptual

models of the regional flow system, (2) inventorying

and field-locating wells for subsurface geological

and hydraulic-head information, (3) compiling and

collecting data to estimate the amounts and dist

tion of various components of the hydrologic bu

(4) compiling and collecting water-level fluctua

information to evaluate the dynamics of regiona

ground-water flow and assess the state of the sy

and (5) developing a computer model to simula

ground-water flow system. This report addresse

first four of these elements.

At the onset of this investigation there we

no published reports on the quantitative regiona

ground-water hydrology of the basin. The only

regional-scale reports prior to this study were a

unpublished descriptive report written for the O

State Engineer (Sceva, 1960) and an assessment 

potential effects of disposal wells in the basin (

1968). All other ground-water reports and studi

were restricted to smaller geographic areas. Sce

works presented a conceptual model of regiona

ground-water flow in the basin that has been lar

corroborated by this study. Although no single 

logic map encompassed the entire study area at 

scale larger than 1:500,000, the study area was 

covered by a montage of maps at scales ranging 

1:100,000 to 1:24,000.

This study benefited from the inventory an

location of about 700 wells by the USGS in the 

1970s as part of a study that was later terminate

lack of funding. In addition, geophysical logs an

odic water-level measurements existed for a sub

those wells. To augment the 700 wells field loca

the start of this investigation, an additional 800 

were inventoried and field located. The geograp

distribution of these 1,500 field-located wells (fi

mirrors the distribution of wells in the basin in g

The highest density of wells occurs on private l

Water levels were measured in located wells wh

possible. Field-located wells provided informat

hydraulic-head distribution and subsurface geol

Approximately 35 wells were geophysically log

and drill cuttings were collected for approximat

70 wells. One-hour specific-capacity tests were 

able for most wells and aquifer tests were cond

on four wells to provide additional information 

hydraulic characteristics.

Water-level data from field-located wells 

elevations of major springs and gaining streams 

used to map hydraulic-head distribution in the r

The resulting distribution map was the basic so

of information regarding the horizontal and ver

directions of ground-water flow.
8

Major components of the hydrologic budget

were either measured or estimated. Recharge from

natural precipitation was estimated by a daily massbalance approach using the Deep Percolation Model

(DPM) of Bauer and Vaccaro (1987). Recharge from

canal leakage was estimated from surface-water

diversion records and estimates of farm deliveries,

in combination with canal seepage studies conducted

by the Bureau of Reclamation (BOR). Farm deliveries

and on-farm losses were derived from consumptiveuse and irrigation-efficiency estimates. On-farm

consumptive use was estimated from crop information

derived from LANDSAT images and crop-water-use

estimates from BOR AgriMet stations in the basin.

The rate and distribution of ground-water

discharge to streams and springs throughout the study

area were estimated using data from active and historic

stream gages, gain/loss studies conducted by OWRD

Central Region staff, and miscellaneous published

streamflow measurements. The rate and distribution

of ground-water pumping was estimated for public

supply and for irrigation uses. Public-supply pumping

was derived from measurements or estimates supplied

by the municipalities and other public water suppliers.

Irrigation pumping was estimated using information

from the OWRD Water-Rights Information System

(WRIS) in combination with on-farm consumptiveuse estimates derived in the manner described above.

Pumping by private domestic wells was estimated

using well-log records and population statistics.

The dynamics of the ground-water flow system,

both at a regional and local scale, were evaluated by

analyzing ground-water-level fluctuations in response

to both long- and short-term hydrologic phenomena

such as variations in climate, individual storms,

canal operation, and pumping. Periodic water-level

measurements were compiled from historic data and

collected from about 100 wells. The frequency of

measurements and the duration of records for wells

varied considerably. There were about 90 wells with

quarterly water-level measurements spanning periods

ranging from a few years to over 50 years. In addition,

there are 16 wells in which water levels were recorded

every 2 hours for periods ranging from a few months

to over 4 years (Caldwell and Truini, 1997).

The chemistry of selected wells, springs, and

canals in the study area was analyzed and interpreted

by Caldwell (1998). This analysis provided additional

insights into the regional ground-water flow system

and into the interaction of ground water and sur

water, including irrigation canals.

Acknowledgments

The authors gratefully acknowledge the su

of the residents of the upper Deschutes Basin th

out this investigation. Particular thanks go to th

hundreds of landowners who allowed access to 

wells for water-level monitoring and sampling. 

Public Works staff of the cities of Bend, Redmo

Sisters, and Madras were extremely helpful in

providing access to their water systems as well 

information on water use and disposal wells. Pr

water companies in the basin were also helpful, 

particular thanks goes to Avion Water Company

Butte Ranch Corporation, Deschutes Valley Wa

District, and Juniper Utility for access to their w

for monitoring, testing, and sampling. Informat

on diversions and water use provided by the ma

irrigation districts in the basin was extremely he

ful and is greatly appreciated. There are several

individuals who have particular knowledge of

certain aspects of geology or water in the basin

who freely shared ideas and insights with the au

This group includes (alphabetically) Larry Chit

Rick Conrey, Mark Ferns, Kyle Gorman, Bob M

Dave Sherrod, and Jan Wick. Larry Chitwood

provided a thoughtful and thorough review of th

report. Lastly, special thanks go to Susan Prowe

with the city of Bend, who handled all the logis

years of quarterly meetings, and to all the peop

showed their interest and support by attending t

GEOLOGIC FRAMEWORK

The storage and flow of ground water are

controlled to a large extent by geology. The prin

geologic factors that influence ground water are 

porosity and permeability of the rock or sedime

through which it flows. Porosity, in general term

is the proportion of a rock or deposit that consis

of open space. In a gravel deposit, this would b

proportion of the volume of the deposit represe

by the space between the individual pebbles and

cobbles. Permeability is a measure of the resista

to the movement of water through the rock or d

Deposits with large interconnected open spaces

as gravel, have little resistance to ground-water 
9

and are therefore considered highly permeable. Rocks

with few, very small, or poorly connected open spaces

offer considerable resistance to ground-water flow

and, therefore, have low permeability. The hydraulic

characteristics of geologic materials vary between

rock types and within particular rock types. For

example, in sedimentary deposits the permeability is

a function of grain size and the range of grain sizes

(the degree of sorting). Coarse, well-sorted gravel

has much higher permeability than fine, silty sand

deposits. The permeability of lava flows can also vary

markedly depending on the degree of fracturing. The

highly fractured, rubbly zones at the tops and bottoms

of lava flows and in interflow zones are often highly

permeable, while the dense interior parts of lava flows

can have very low permeability. Weathering and

secondary mineralization, which are often a function

of the age of the rock, can strongly influence permeability. Sedimentary deposits or lava flows in which

the original open spaces have been infilled with

secondary minerals can have very low permeability.

Geologic properties that influence the movement

of ground water within a flow system can also define

the boundaries of the system. Terranes consisting of

predominantly low-permeability materials can form

the boundaries of a regional flow system.

This section briefly describes the geologic

framework of the regional ground-water flow system

in the upper Deschutes Basin, including a brief

description of the major geologic units, geologic

structure, and the geologic factors controlling the

flow-system boundaries.

Geologic Controls on Regional Ground-Water Flow

The upper Deschutes Basin has been a region

of volcanic activity for at least 35 million years

(Sherrod and others, in press), resulting in complex

assemblages of volcanic vents and lava flows, pyroclastic deposits, and volcanically derived sedimentary

deposits (fig. 4). Volcanic processes have created

many of the present-day landforms in the basin.

Glaciation and stream processes have subsequently

modified the landscape in many places.

Most of the upper Deschutes Basin falls within

two major geologic provinces, the Cascade Range and

the Basin and Range Province (Orr and others, 1992).

The processes that have operated in these provinces

have overlapped and interacted in much of the u

Deschutes Basin. The Cascade Range is a north

trending zone of compositionally diverse volcan

eruptive centers and their deposits extending fro

northern California to southern British Columb

Prominent among the eruptive centers in the De

chutes Basin are large stratovolcanoes such as N

Middle, and South Sister, and Mount Jefferson, 

of which exceed 10,000 ft in elevation. The Cas

Range is primarily a constructional feature, but 

growth has been accompanied, at least in places

subsidence of the range into a north-south trend

graben (Allen, 1966). Green Ridge is the easter

escarpment of one of the graben-bounding fault

The Basin and Range Province is a region of cr

extension and is characterized by subparallel fa

bounded down-dropped basins separated by fau

block ranges. Individual basins and intervening 

are typically 10 to 20 miles across. The Basin a

Range Province, which encompasses much of t

interior of the Western United States, extends fr

central Oregon south through Nevada and weste

Utah, and into the southern parts of California,

Arizona, and New Mexico. Although the Basin 

Range Province is primarily structural, faulting 

been accompanied by widespread volcanism. T

major stratigraphic units in the upper Deschutes 

are described below in approximate order of the

The oldest rocks in the upper Deschutes B

study area (unit Tjd in fig. 4) are part of the late

Eocene to early Miocene John Day Formation a

consist primarily of rhyolitic ash-flow tuffs, lav

flows, tuffaceous sedimentary rocks, and vent

deposits. The John Day Formation ranges in ag

22 to 39 million years and is as much as 4,000 f

(Smith and others, 1998). Rocks of the John Da

Formation have very low permeability because 

tuffaceous materials are mostly devitrified (chan

clays and other minerals) and lava flows are wea

and contain abundant secondary minerals. Beca

of the low permeability, ground water does not 

move through the John Day Formation, and the 

acts as a barrier to regional ground-water flow. 

John Day Formation constitutes the eastern and

northern boundary of the regional ground-water 

system. The John Day Formation, or equivalent 

are presumed to underlie much of the upper Des

Basin and are considered the lower boundary of 

regional flow system throughout much of the st

area.
11

The Prineville basalt (unit Tpb in figure 4) overlies the John Day Formation in the northeastern part

of the study area. Radiometric techniques indicate

that the Prineville basalt is 15.7 million years old

(Smith, 1986). The Prineville basalt, which is up to

700 ft thick, is locally fractured, contains permeable

interflow zones, and is locally an important aquifer.

0 5 10 MILES

0 5 10 KILOMETERS

EXPLANATION

Geologic unit present at land surface

	 Quaternary alluvium and glacial deposits;

		 Quaternary to late Tertiary landslide deposits

	 Quaternary sediments and sedimentary rocks,

		 undivided

	 Quaternary pyroclastic deposits

	 Quaternary to late Tertiary basaltic to andesitic lava

	 Quaternary and late Tertiary rhyolitic to dacitic lava

	 Quaternary and late Tertiary vent deposits,

		

	 Late Tertiary sediments and sedimentary rocks,

		 undivided, mostly of the Deschutes Formation

	 Tertiary basaltic to andesitic lava

	 Tertiary rhyolitic to dacitic lava

	 Tertiary pyroclastic deposits

	 Tertiary vent deposits

	 Prineville basalt

	 Early Tertiary volcanic deposits, mainly the

		 John Day Formation

	 Geologic fault, dashed where inferred,

		 dotted where concealed

	 Outline of La Pine and Shukash structural basins,

		 inferred from gravity data

Qalg

Qs

Qp

QTba

QTrd

QTv

Tba

Tds

Trd

Tp

Tv

Tpb

Tjd

NOTE: Geology generalized from:

	 MacLeod and Sherrod, 1992;

	 MacLeod and others, 1995;

	 Sherrod, 1991;

	 Sherrod and Smith, 2000;

	 Sherrod and others, in press;

	 Smith, 1987; Smith and Hayman, 1987;

	 Swanson, 1969, and

	 Walker and others, 1967.

	 Shukash and La Pine outline from Richard Couch,

	 Oregon State University, personal commun., 1996.

The Deschutes Formation, which overlies the

Prineville basalt, consists of a variety of materials

deposited in an alluvial basin east of the Cascade

Range, including lava flows, ignimbrites, fallout

tephra, debris flows, hyperconcentrated flood deposits,

and alluvium. Most of the deposits originated in the

Cascade Range and were shed eastward into the basin,

but some originated from intrabasin eruptive centers or

were eroded from older (John Day Formation) uplands

to the east. The Deschutes Formation was deposited in

a rapidly filling basin with a constantly changing drainage system between about 4.0 and 7.5 million years

ago (Smith, 1986). Deposition of many units within

the formation was restricted to canyons and other

short-lived topographic lows. Consequently, individual

strata within the Deschutes Formation typically have

limited geographic distribution resulting in a heterogeneous sequence. Most of the areas mapped as Tds,

Tba, Tp, and Tv in figure 4 are generally recognized

as part of the Deschutes Formation. Some areas so

mapped in southern part of figure 4 are not generally

considered part of the Deschutes Formation, but are

composed of rocks similar in composition and age

to the Deschutes Formation, and likely have similar

hydrologic characteristics.

Strata within the Deschutes Formation were

deposited in three main depositional environments

(Smith, 1986). The westernmost depositional environment was a broad plain adjacent to the Cascade Range,

on which a variety of materials were deposited, including flood and debris-flow deposits, ignimbrites, fallout

tephra, and lava flows. The ancestral Deschutes River

was another depositional environment, occurring along

the eastern margin of the alluvial plain. Deposits in the

ancestral Deschutes River environment include wellsorted conglomerates and coarse sandstone, fine sandstone, mudstone, and intracanyon lava flows. A third

depositional environment existed along the inactive

eastern margin of the basin. Here, material eroded from

the highland of older rock to the east (mostly John Day

Formation) was redeposited, resulting in beds of poorly

sorted angular gravel and sand, reworked pyroclastic

debris, and fine-grained sediment.

The Deschutes Formation is the principal aquifer

unit in the upper Deschutes Basin. The unit ranges

in thickness from zero where it contacts the underlying

John Day Formation or Prineville basalt to over

2,000 ft at its westernmost exposure at Green Ridge.

Permeable zones occur throughout the Deschutes

Formation. The lava flows, vent deposits, and sand and

gravel layers in the Cascade Range-adjacent alluvial
12

plain facies and the ancestral Deschutes River facies

are locally highly permeable. Two sequences of lava

flows in the Deschutes Formation, the Opal Springs

basalt, which is up to 120 ft thick, and the Pelton

basalt, which may locally exceed 400 ft in thickness,

are notable aquifers and locally discharge large

amounts of water where exposed in the canyons of the

Deschutes and Crooked Rivers. The inactive margin

facies is less permeable because of poor sorting and a

high degree of weathering.

Rhyolite and rhyodacite domes (unit Trd in

figure 4) occur in the north-central part of the study

area and are locally interbedded with the Deschutes

Formation. These materials form Cline Buttes and also

crop out in the area between the Deschutes River and

Squaw Creek north of Lower Bridge. These rocks are

locally highly fractured and permeable. Numerous

springs discharge from permeable zones in this unit

where it is exposed in the canyon of the Deschutes

River near Steelhead Falls (Ferns and others, 1996).

The Cascade Range and volcanic deposits of

similar age elsewhere in the basin overlie the Deschutes Formation and constitute the next major composite stratigraphic unit. These deposits include units

Qp, QTba, QTrd, and QTv in figure 4. This composite

unit, which is likely several thousand feet thick,

is composed of lava flows, domes, vent deposits,

pyroclastic deposits, and volcanic sediments. Most

are Quaternary in age (younger than 1.6 million years

old). This unit includes the entire Cascade Range and

Newberry Volcano to the east. Much of this material

is highly permeable, especially the upper several

hundred feet. Permeability of the unit is greatly

reduced at depth beneath the Cascade Range, however,

due to hydrothermal alteration and secondary mineralization (Blackwell and others, 1990; Blackwell, 1992;

Ingebritsen and others, 1992). Temperature gradient

data (Swanberg and others, 1988) and hydrothermal

mineralization studies (Keith and Barger, 1988, 1999)

suggest a similar loss of permeability at depth beneath

Newberry Volcano. The top of the region at depth

beneath the Cascade Range and Newberry Volcano

where permeability is reduced by several orders of

magnitude due to hydrothermal mineralization is considered, for the purposes of this study, to be the base of

the regional ground-water flow system in these areas.

The Cascade Range and volcanic deposits of

similar age are highly permeable at shallow depths.

The near-surface deposits are often highly fractured or

otherwise porous and largely lack secondary mineralization. The Cascade Range is the principal gro

water recharge area for the upper Deschutes Ba

and these deposits are the principal avenue by w

most ground water moves from the recharge are

into the basin. Because there are very few wells 

Cascade Range and on Newberry Volcano, ther

little information on the distribution of hydrauli

or subsurface conditions.

The youngest units in the upper Deschutes 

are Quaternary sedimentary deposits. These dep

include alluvium along modern flood plains, lan

deposits, and glacial drift and outwash (unit Qa

figure 4). Undifferentiated Quaternary sedimen

deposits resulting from a variety of depositiona

processes are mapped as Qs in figure 4. Many o

Quaternary sedimentary deposits in the basin ar

too thin or discontinuous to affect regional grou

water flow. However, glacial deposits, particula

outwash deposits, are sufficiently thick and wid

spread to be significant. Glacial deposits, gener

porous and permeable, are an important source

of ground water along the margin of the Cascad

Range, for example in the area around the city o

Sisters. Alluvial sand and gravel deposits also f

an important aquifer in the La Pine subbasin (fi

Geologic structure, principally faults and 

zones, can influence ground-water flow. Fault z

can act either as barriers to or conduits for grou

water flow, depending on the nature of the mate

and between the individual fault planes. Faults 

commonly affect ground-water flow by juxtapo

rocks of contrasting permeability or by affectin

patterns of deposition. Structural basins caused 

faulting can act as depositional centers for large 

nesses of sediment or lava that may influence re

ground-water flow. Faults do not always influen

ground-water flow; there are regions in the upp

Deschutes Basin where ground-water flow appe

unaffected by the presence of faults.

There are four prominent fault zones in the 

Deschutes Basin (fig. 4). Green Ridge, north of 

Butte, is a prominent north-south trending escar

caused by faulting along the margin of the Casc

graben. The region to the west of Green Ridge 

dropped as much as 3,000 ft (Conrey, 1985). Th

movement has juxtaposed rock materials of con

ing permeability, and subsidence west of the fau

tem has created a depositional basin for accumu

of volcanic and glacial materials from the Casc

Range. A large amount of ground water dischar
13

to the Metolius River along the western side of the

Green Ridge escarpment. It is possible that the groundwater discharge occurs because the Green Ridge fault

zone acts as a barrier to the eastward flow of ground

water from the Cascade Range. It is also possible

that discharge occurs because the western side of the

escarpment is a regional topographic low.

The Sisters fault zone is a north-northwest trending zone of normal faults that extends from the north

flank of Newberry Volcano to the south end of Green

Ridge near Black Butte. Escarpments of some faults

along the Sisters fault zone have impounded lava flows

from the Cascade Range and prevented flow into lowerelevation areas toward the northeast. Escarpments

along the Sisters fault zone also have caused local accumulation of glacial sediments. Although the Sisters

fault zone affects the occurrence of shallow ground

water by controlling the deposition of glacial sediment,

it does not appear to affect ground-water flow at depth.

The Brothers fault zone is a major northwesttrending zone of normal faults that extends from southeastern Oregon to the north flank of Newberry Volcano.

Faults along this zone are covered by lava flows

from Newberry Volcano and do not appear to offset

those flows. The influence of the Brothers fault zone

on regional ground-water flow is unknown.

The Walker Rim fault zone is a major northeasttrending zone that extends from Chemult to the south

flank of Newberry Volcano. The region to the west has

dropped as much as 2,500 ft (feet). The influence of

this fault zone on ground-water flow is unknown.

The La Pine and Shukash structural basins (fig. 4)

are complex graben structures extending from Newberry Volcano to the crest of the Cascade Range. Much

of what is known of these features is from interpretations of gravity data by Couch and Foote (1985, and

written commun., 1996). The La Pine graben is a

present-day landform, and well data shows that it has

accumulated over 1,000 ft of sediment, much of which

is fine grained. The Shukash basin, in contrast, has no

surface expression, is mostly covered by younger volcanic and glacial deposits, and its existence is inferred

largely from gravity data. The sediment thickness at

the center of the basin is inferred to be about 2,500 ft.

The nature of sediment fill is poorly known, but where

exposed or drilled, the sediment in the Shukash basin is

similar to that of the La Pine basin. The fine-grained

sediment fill in the La Pine and Shukash basins has

low permeability. The presence of large springs on the

margins of the La Pine and Shukash basins may be due

to the juxtaposition of permeable Cascade Rang

volcanic rocks with the low-permeability basin-

deposits. The faults bounding both of these grab

are largely obscured by younger volcanic depos

Hydraulic Characteristics of Subsurface Mater

As described in the preceding section, geo

materials possess certain hydraulic characteristi

control the movement and storage of ground wa

This section describes quantitative terms that rep

those characteristics and presents estimates or r

of values of those terms for various materials in 

upper Deschutes Basin. A more thorough discu

of the terms used to describe the hydraulic char

tics of aquifers and aquifer materials can be fou

any basic ground-water hydrology text such as 

and Cherry (1979), Fetter (1980), or Heath (198

The term permeability was introduced in t

section as a measure of the resistance to fluid fl

offered by a particular rock type. Permeability i

intrinsic property of the rock type, and is indep

of the fluid properties. In ground-water studies, 

term hydraulic conductivity is used more comm

than permeability. The hydraulic conductivity t

includes both the properties of the rock (the intr

permeability) and the properties of the water, su

as viscosity and density. Hydraulic conductivity 

defined as the volume of water per unit time tha

will pass through a unit area of an aquifer mate

response to a unit hydraulic-head gradient. Hyd

conductivity has the units of volume per unit tim

(such as cubic feet per day) per unit area (such 

square feet), which simplifies by division to len

per unit time (such as feet per day). Hydraulicconductivity values for aquifer materials comm

span several orders of magnitude from less than

0.1 ft/d (feet per day) for fine sand and silt to ov

1,000 ft/d for well-sorted sand and gravel.

When discussing aquifers instead of rock 

the hydraulic conductivity is often multiplied b

aquifer thickness to derive a term known as tran

sivity. Transmissivity is defined as the volume o

per unit time that will flow through a unit width 

aquifer perpendicular to the flow direction in re

to a unit hydraulic-head gradient. Transmissivit

units of volume per unit time (such as cubic fee

day) per unit aquifer width (such as feet) which 

plifies to length squared per unit time (such as s

feet per day).
14

The storage characteristics of an aquifer are

described by the storage coefficient. The storage

coefficient is defined as the volume of water an aquifer

releases from, or takes into, storage per unit area of

aquifer per unit change in head. The volume of water

has units of length cubed (such as cubic feet), the

area has units of length squared (such as square feet),

and the head change has units of length (such as feet).

Thus, the storage coefficient is dimensionless. Storage

coefficients typically span several orders of magnitude

from 10-4 for aquifers with overlying confining units,

to 0.1 for unconfined aquifers.

Aquifer Tests

The hydraulic characteristics of subsurface

materials in the basin have been estimated using data

from aquifer tests, some of which were conducted as

part of this study, and specific-capacity tests conducted

by drillers upon completion of new wells. An aquifer

test consists of pumping a well at a constant rate and

measuring the change in water level (the drawdown)

with time. The data collected allow generation of a

curve showing the change in drawdown as a function

of time. Similar data are collected after the pumping is

stopped, allowing generation of a curve showing the

water-level recovery as a function of time. These data

are collected not only from the pumped well, but from

nearby wells (called observation wells) in which the

water level may be affected by the pumping. Analysis

of the drawdown and recovery curves in the pumped

well and observation wells provides estimates of the

transmissivity and storage coefficient of the aquifer.

Four aquifer tests were conducted as part of this

study (fig. 5). Each involved pumping a large-capacity

public-supply well and observing drawdown and

recovery in nearby nonpumped wells. In addition,

results from seven aquifer tests conducted by private

consultants were available. A common problem

encountered in many of the tests was the inability to

stress the aquifer sufficiently to induce an interpretable

effect in the observation wells. In other words, the

aquifer transmissivity is so large in some places that

pumping a well in excess of 1,000 gal/min (gallons per

minute) may produce only a few hundredths of a foot

of drawdown in an observation well just a few hundred

feet from the pumped well.

Aquifer tests were conducted for this study on

wells belonging to the cities of Madras, Redmond, and

Bend, as well as Juniper Utilities, a privately ow

water utility. Each of the tests is summarized in 

and described in the following paragraphs. The 

tion of the tested wells is shown in figure 5.

The city of Madras test involved pumping 

Well No. 2 at 351 gal/min for 3 days and monit

the response in the pumped well and in an obser

well 250 ft from the pumped well. The pumped 

produces from a layer of sand and gravel at the 

of a sequence of lava flows. The producing sedi

are part of the inactive-margin facies of the Des

Formation (fig. 5). Both the pumped well and th

observation well showed good responses to the

pumping, with maximum drawdowns of 36.20 

17.67 ft respectively. The drawdown and recove

curves were typical of a confined aquifer (Lohm

1979). The test yielded a transmissivity estimat

1,700 to 2,500 ft2/d (square feet per day) and a s

coefficient estimate of 0.0001 to 0.0002.

The city of Redmond test consisted of pum

City Well No. 3 at 1,141 gal/min for 3 days and

monitoring the response in the pumped well an

observation well 350 ft from the pumped well. 

well produces from a combination of lava flows 

sand and gravel layers in the Cascades-adjacent 

vial plain or ancestral Deschutes River facies of 

Deschutes Formation. Interpretation of the resu

this test was complicated by the very small resp

in the observation well. Total drawdown in the 

vation well after 3 days of pumping was only 0

which is close to the range of observed pre-test 

level fluctuations caused by external influences s

barometric pressure changes and earth tides. Dr

down in the pumping well (11.67 ft) was domin

by well losses (excessive drawdown in the well 

due to well inefficiency) so only the recovery d

from the pumped well was usable. The drawdow

and recovery curves resulting from this test wer

typical of a confined aquifer. The drawdown fol

the typical Theis curve (Lohman, 1979) near th

beginning of the test, but later deviated from the 

indicating that drawdown was less than would b

expected for a confined aquifer. The exact cause 

behavior is unknown, but similar behavior is ob

in aquifers where drainage of water from overly

strata cause a delayed-yield response (Neuman, 

Analysis of the test results yielded a transmissiv

estimate of 2.0 × 105 ft2/d to 3.0 × 105 ft2/d, an

storage coefficient estimate of 0.05.
16

Sources for tests by private consultants:1 Century West Engineering Corporation, 1990, Regional hydrogeologic investigation for the proposed Shadow Mountain R.V. Park, Sisters, Oregon.2 Cascade Earth Sciences Limited, 1994, City of Redmond, Oregon, wastewater treatment system expansion: hydrogeologic characterization report.3 Century West Engineering Corporation, 1990, Preliminary pump test data and groundwater material for the proposed Shadow Mountain R.V. Park, Sisters, Or4 Century West Engineering Corporation, 1985, Assessment of water availability, Redmond, Oregon.5 W and H Pacific, 1994, Brooks Resources Corporation groundwater appropriation claim of beneficial use and site report, Permit No. G-1106.6 Century West Engineering Corporation, 1984, Water-supply study for Mount Bachelor.7 CH2M, 1964, A report on an engineering study of the municipal water system, city of Bend, Oregon.

Table 1. Summary of selected aquifer tests in the upper Deschutes Basin, Oregon[OWRD well no., Oregon Water Resources Department well number; gpm, gallons per minute; Analysis method: T, Theis non-equilibrium curve matching; SL, straigSC, Theis solution using specific-capacity data (Lohman, 1979). Test conducted by: S, study team; C, private consultant. ft2/d, square feet per day; ft, feet; ft/d, feet p

---, value not determined; *, time-averaged pumping rate]

Well

number

OWRD

well no.

Well

name

Discharge

(gpm)

Duration

(hours)

Drawdown

Distance

from

pumped

well

Analysis

method

Test

conducted

by

Transmissivity

(ft2/d)

Storage

coefficient

11S/13E-01BCA2 JEFF0427 City of Madras

Well 2

351 72 17.67 250 T, SL S 1.7 × 103 to

2.5 × 103

0.0001 to0.0002

San

14S/10E-30DDB2 DESC1835 Cascade

Meadows

1,000 4.5 29.3 0 SC C1 5 × 104 --- Ma

14S/12E-13DC DESC8593 City of Redmond

MW-8

11.4 24 8.25 0 S C2 1.8 × 102 --- Bas

15S/10E-05BBB DESC2999 Tollgate 1,210 48 4.5 0 SC C3 1 × 104 --- Gla

& m

15S/13E-20CDC DESC0407 City of Redmond

Well 4

* 2,751 72 1.8 844 T C4 6 × 103 .1 San

15S/13E-22CBA2 DESC3951 City of Redmond

Well 3

1,141 72 .16 350 T, SL S 2.0 × 105 to

3.0 × 105

.05 San

lava

17S/11E-11BAs DESC1304 Awbrey Butte 225 24 .65 0 SC C5 1 × 105 --- Bas

min

18S/9E-20BDA DESC5215 Mount Bachelor 110 18 39 0 SC C6 5 × 102 --- Bas18S/12E-BDB1 DESC5576 Brooks-Scanlon

No. 1

1,270 17 7.61 0 SC C7 5 × 104 --- Lav

18S/12E-07DBD2 DESC9108 City of Bend

Rock Bluff

722 24 .06 210 --- S --- --- Bas

18S/12E-16BCC3 DESC5613 Juniper Utility 1,300 3 1.14 35 --- S --- --- Lav
17

The city of Bend test involved pumping one

of the wells at the city’s Rock Bluff well field south

of town at 722 gal/min for a period of 24 hours. This

well produces from basaltic lava and cinders of the

Deschutes Formation, which is predominantly lava at

this location. The response was measured in a nearly

identical observation well 210 ft from the pumped

well. There was no access to the pumped well for

water-level measurements. The drawdown in the

observation well was less than 0.06 ft, which is well

within the range of water-level fluctuations caused

by external influences such as barometric pressure

changes and earth tides. The small drawdown due to

pumping could not be satisfactorily separated from

the water-level fluctuations due to external influences,

and no quantitative analysis was possible. The small

drawdown in this well, however, suggests a large

transmissivity of a magnitude similar to that estimated

from the city of Redmond well test.

The fourth aquifer test conducted for this study

involved pumping a production well belonging to

Juniper Utilities, south of Bend, at 1,300 gal/min for

just over 3 hours. This well produces from basaltic

lava with minor interbedded cinders which are likely

correlative to the Deschutes Formation. Drawdown

and recovery were measured in an observation well

35 ft from the pumped well and open to the same

water-bearing strata. There was no access for waterlevel measurements in the pumped well. The drawdown in the observation well, which totaled 1.14 ft

after 3 hours, did not follow the Theis curve for a

confined aquifer (Lohman, 1979). The drawdown

departed from the Theis curve about 7 minutes into

the test in a manner indicating that drawdown was

less than would be expected for a confined system.

After about 50 minutes the water level stabilized and

drawdown did not increase for the duration of the test,

indicating that the cone of depression encountered

a source of recharge equal to the well discharge.

The likely source of recharge was leakage from large

(hundreds of cubic feet per second) unlined irrigation

canals within 3,000 ft of the pumped well. Analysis

of recovery data also indicated the aquifer received

recharge during the test. The short duration of this

test and the atypical response in the observation

well precluded a reliable estimation of hydraulic

parameters. The relatively small total drawdown in

the observation well suggests a large transmissivity.

Results from seven additional aquifer test

conducted by consultants are summarized in tab

Most of these tests were affected by one or mor

problems such as insufficient response in obser

wells, measurement errors, variable pumping ra

effects of well losses in the pumping well, and

recharge effects. Time-drawdown data from five 

tests were not suitable for type-curve analysis, b

tests did allow calculation of the specific capaci

the wells. Specific capacity is a general measur

well performance and is calculated by dividing 

rate of pumping by the amount of drawdown an

typically has units of gallons per minute per foo

drawdown. Transmissivities were estimated fro

specific-capacity data using an iterative techniq

based on the Jacob modified nonequilibrium fo

(Ferris and others, 1962, p. 98; Vorhis, 1979).

Transmissivity estimates from aquifer test

affected by well construction and the thickness 

aquifer open to the well. In order to allow mean

comparisons between aquifer tests, transmissivi

estimates can be normalized by dividing them b

the length of the open interval below the water 

in the pumped well to derive an estimated hydr

conductivity. Hydraulic-conductivity values so 

lated are included in table 1. Hydraulic-conduct

estimates derived from aquifer tests vary more t

two orders of magnitude, from less than 10 to n

1,900 ft/d. The variation in hydraulic conductiv

subsurface materials is undoubtedly much great

indicated by the tests. Production zones in well

not a true sample of the range in hydraulic conductivities in the subsurface because the wells a

selectively open to the most permeable strata an

permeable zones are not represented.

Hydraulic-conductivity values from the av

tests do not correlate well with rock type. Tests 

wide range of values from both volcanic and se

tary aquifers. This is not surprising because hyd

conductivities of both types of materials can ran

over several orders of magnitude (Freeze and C

1979, table 2.2). The small number of tests prec

determination of the spatial distribution of hydr

conductivity. The highest hydraulic-conductivit

values, however, are associated with Deschutes

Formation materials, including basaltic lava and 

deposits, and sand and gravel deposits likely be

ing to the ancestral Deschutes River channel fac

described by Smith (1986).
18

Well-Yield Tests

Another source of information on subsurface

hydraulic characteristics are the well-yield tests conducted by drillers and reported on the well logs submitted on completion of all new wells. Well-yield tests

generally consist of a single drawdown measurement

taken after a well has been pumped at a specified rate

for a specified length of time, typically 1 hour. Wellyield tests allow determination of a well’s specific

capacity, which can be used to estimate transmissivity

as described previously. Specific capacity is only a

semiquantitative measure of well performance in that

it can vary with pumping rate. Specific-capacity values

can be used to calculate only rough estimates of the

aquifer transmissivity and provide no information on

the aquifer storage characteristics. Although transmissivity values calculated from specific-capacity tests are

only approximate, they can be used to evaluate the relative differences in hydraulic characteristics between

different geographic areas if data are available from a

sufficient number of wells.

Well-yield tests were evaluated from 1,501

field-located water wells (raw data are in Caldwell

and Truini, 1997). Of these tests, 390 were air-lift

tests, in which the water is blown out of the well using

compressed air, precluding measurement of drawdown

and calculation of specific capacity. An additional 152

tests had information that was incomplete in some

other way. Of the 959 remaining yield tests, 453 had

pumping (or bailing) rates that did not sufficiently

stress the aquifer to produce a measurable effect in the

well, and zero drawdown is indicated on the well log.

This precludes calculation of a specific ca

because if drawdown is zero then specific capac

infinite, a physical impossibility. Eliminating w

with drawdown shown as zero from the data set 

have selectively removed wells representing the 

transmissive areas. To avoid biasing the data in 

manner, wells with zero drawdown were arbitra

assigned a drawdown of 1 ft, which is the limit 

precision to which most drillers report water lev

and probably the limit to which it is measured d

bailer tests. Statistics for specific capacities der

from well-yield tests in the study area and from

various subareas within the study area are show

table 2.

A map showing the geographic distributio

transmissivity estimates derived from well-yield 

can be used to help understand spatial variation

aquifer characteristics. When creating such map

is important to include only wells with compara

construction. Certain wells, such as high-yield

municipal and irrigation wells are constructed t

very efficient, and consequently have higher spe

capacities than small-yield household wells in t

same aquifer. Therefore, it is desirable to use on

wells with comparable construction when creat

maps showing transmissivities estimated from

specific-capacity data.

The geographic distribution of transmissiv

estimated from specific capacities of 623 house

wells is shown in figure 5. Although a wide ran

of transmissivity values occurs throughout the

areas represented, some subtle patterns are appa

Table 2. Statistics for transmissivities (square feet per day) estimated from specific-capacity data for subareas in the u

Deschutes Basin, Oregon

[*, includes wells outside the listed subareas]

Area Minimum

25th

Percentile Median

75th

Percentile Maximum

Num

of w

La Pine Subbasin Alluvium 7.1 342 901 1,953 114,297 1

Deschutes Formation West 11.4 617 1,917 3,587 1,458,724 3

Deschutes Formation East 12.6 1,099 2,337 4,063 221,887 2

Inactive Margin 1.1 46.2 796 2,225 59,683 

All located wells* 1.1 518 1,821 3,660 1,458,724 9
19

The La Pine subbasin, the area just north of Bend,

Jefferson County, and the eastern margin of the study

area show the highest incidence of wells with low

transmissivity values. The areas east of Bend, between

the Crooked and Deschutes Rivers near Redmond, and

west of Sisters show the highest incidence of high

transmissivity wells. This distribution is consistent

with the results of aquifer tests and with the regional

geology. The areas where transmissivities appear to be

slightly higher coincide with regions of coarse-grained

sedimentary deposits, such as the glacial outwash west

of Sisters and the ancestral Deschutes River channel

deposits in the Redmond area. The areas where

transmissivities appear lower coincide, at least in

part, with regions where fine-grained materials

predominate, such as the La Pine subbasin, or regions

where older rock or sediments derived from older rock

predominate, such as the eastern and northern parts of

the upper Deschutes Basin.

The aquifer tests described above provide information on aquifer characteristics at specific locations,

and taken as a group provide a general picture of the

minimum range of conditions and of geographic variations in the areas represented. The specific-capacity

values from well-yield tests provide a rough picture

of the geographic distribution of transmissivity. The

aquifer-test and specific-capacity data described in

this section, however, represent only a small part of

the flow system. There are large geographic areas

in the upper basin, such as the Cascade Range and

Newberry Volcano area, where there are virtually no

data. Moreover, in areas of the upper Deschutes Basin

where wells are plentiful, most wells penetrate only

the upper part of the saturated zone and may not be

representative of the deep parts of the flow system.

GROUND-WATER RECHARGE

The Deschutes Basin ground-water flow system

is recharged by infiltration of precipitation (rainfall

and snowmelt), leakage from canals, infiltration of

applied irrigation water that percolates below the root

zone (on-farm losses), and leakage from streams.

Recharge from all of these processes is discussed in

this section. The amounts of recharge from each of the

processes cannot be simply summed to determine the

net recharge for the upper Deschutes Basin because

some water cycles into and out of the ground-water

system twice. For example, the water that recharges

the ground-water system through canal leakage

originates as streamflow, a large percentage of w

originates as springflow in the Cascade Range. 

ground water supplying the springs originates f

infiltration of precipitation in the Cascade Rang

Infiltration of Precipitation

Recharge from precipitation occurs where 

or snowmelt infiltrates and percolates through t

zone and, eventually, reaches the saturated part 

ground-water flow system. Recharge is the quan

water remaining after runoff and evapotranspira

take place.

The spatial and temporal distribution of g

water recharge to the upper Deschutes Basin fro

infiltration of precipitation were estimated for w

years 1962–97 using a water-balance model. Th

model, referred to as the Deep Percolation Mod

DPM, was developed by Bauer and Vaccaro (19

for a regional analysis of the Columbia Plateau 

system in eastern Washington. The DPM is bas

on well-established empirical relations that qua

processes such as interception and evaporation, 

accumulation and melt, plant transpiration, and 

The DPM has been successfully applied to estim

regional recharge for studies of the Goose Lake

Basin in Oregon and California (Morgan, 1988)

Portland Basin in Oregon and Washington (Sny

and others, 1994), and several other areas in Or

and Washington. A detailed description of the a

tion of the DPM to the Deschutes Basin, includ

data input, can be found in Boyd (1996). The fo

sections provide a summary of the methodology 

results.

The DPM was applied to the entire upper 

chutes Basin by subdividing the basin into 3,47

sized grid cells with dimensions of 6,000 ft by 6

(fig. 6). The DPM computed a daily water balan

each cell using input data describing the locatio

elevation, slope, aspect, mean annual precipitat

land cover, and soil characteristics of each cell.

Daily data (precipitation, maximum and minim

temperature, solar radiation) from six weather s

(table 3) in the basin were used to compute dail

moisture input and potential evapotranspiration 

each cell. The six climate stations used were se

because they had the longest periods of record w

fewest occurrences of missing data among stati

the basin. Climate data were obtained from the 

Climate Service (1999).
21

The DPM requires that several types of data

be specified for each cell: long-term average annual

precipitation, land-surface elevation, slope, aspect,

land-cover type, and soil type. Long-term average

annual precipitation at each cell was derived from

a statewide distribution for the 1961–90 period

estimated by the Oregon Climate Service using the

PRISM model (Daly and Nielson, 1992). PRISM

uses digital topographic data to account for orographic

effects on precipitation. The DPM uses the ratio of

the long-term annual average precipitation at the cell

to the long-term average at each climate station to

interpolate daily precipitation values at each cell.

The mean elevation, slope, and aspect of each

cell were calculated from 90-meter digital elevation

data using a geographic information system (GIS).

Elevation was used with temperature lapse rates

to interpolate daily temperature values at each cell

from the nearest climate stations. Slope at each cell

was used to compute runoff and aspect was used to

estimate incident solar radiation in the calculation

of potential evapotranspiration.

Land-cover data from the Oregon Gap Analysis

Program (J. Kagan, Oregon Natural Heritage Program,

written commun., 1992) was used to specify four

land-cover types in the model: forest, sage and juniper,

grass, and surface water. These types covered 61, 36,

2, and 1 percent of the basin, respectively. Recharge

from irrigated croplands was not estimated using

DPM; estimates of recharge to these areas from canal

leakage and on-farm losses are described later in this

section. For each land-cover type, the maximum plant

rooting depth, foliar cover fraction, and intercep

storage capacity were specified based on literat

values (Boyd, 1996).

A statewide soil database (STATSGO)

(U.S. Department of Agriculture, 1991) was use

specify soil type and associated parameters at e

cell. A cluster analysis was used to aggregate th

26 general soil types found within the basin into

10 hydrologic soil types (Boyd, 1996). For each

hydrologic soil type, thickness, texture, field ca

specific yield, horizontal hydraulic conductivity

vertical hydraulic conductivity were specified.

The DPM was used to compute daily wate

balances at each cell from January 1961 throug

November 1997. The daily recharge values wer

used to compute mean monthly and annual rech

values.

The distribution of mean annual recharge 

water years 1993–95 (fig. 6) illustrates the stron

relation between precipitation (fig. 3) and recha

Recharge for the 1993–95 period was calculate

correspond to the calibration period for a steady

numerical ground-water flow model. Computed

recharge from precipitation ranged from less th

1 in./yr in the lower elevations, where annual pr

tation is less than 12 inches, to more than 130 i

in the high Cascade Range, where soils are thin 

precipitation locally exceeds 200 inches. The m

recharge for the basin during the 1993–95 wate

was 10.6 in./yr; converted to a mean annual val

the 4,500 mi2 basin, this is the equivalent of abo

3,500 ft3/s (cubic feet per second).

Table 3. Weather stations used for estimation of recharge from infiltration of precipitation with the Deep Percolation M

[ID, identification; X, data collected]

Station name Station ID Elevation, in feet Precipitation data Temperature data Solar-radiat

Bend 0694 3,650 X X

Brothers 1067 4,640 X

Madras 5139 2,230 X

Prineville 6883 2,840 X X

Redmond 7062 3,060 X X X

Wickiup Dam 9316 4,360 X X
22

Between 1962 and 1997, estimated recharge

ranged from less than 3 inches in the drought years of

1977 and 1994 to nearly 23 inches in 1982 (fig. 7).

The mean for the 26-year period was 11.4 in./yr,

which converts to an annual rate of about 3,800 ft3/s.

The estimated evapotranspiration for the basin is relatively constant from year to year because the effects of

above or below normal precipitation are dampened by

storage in the soil moisture zone. Runoff is a relatively

small component of the total water budget in the

Deschutes Basin due to high infiltration rates of the

permeable volcanic soils. The Deschutes and Metolius

Rivers are noted for their extraordinarily constant

flows that are sustained primarily by ground-water

inflow. Recharge averages about 35–40 percent of

annual precipitation within the basin, but ranges from

less than 5 percent at low elevations, where potential

evapotranspiration greatly exceeds precipitation, to

as much as 70 percent at higher elevations, where

annual precipitation may be several times greater than

potential evapotranspiration.

Manga (1997) developed a physically based

model using the Boussinesq equation (Boussinesq,

1904) to estimate recharge rates within the contributing areas of four spring-dominated streams tribu

the Deschutes River above Benham Falls. Resu

agreed well with those from the DPM for the ar

Within the inferred contributing areas to all fou

streams, mean DPM recharge was 29 in./yr (196

and mean recharge estimated by Manga was 28 

(1939–91). Manga’s estimated recharge average

56 percent of precipitation within the contributi

area of the four streams, while the DPM recharg

approximately 45 percent of precipitation withi

same area.

About 84 percent of recharge from infiltra

of precipitation occurs in the Deschutes Basin be

November and April (fig. 8). According to the D

recharge rates peak in December and again in M

April. The December recharge peak results from 

percolation of precipitation after heavy fall rain

early winter snowfall and melt have saturated so

After January, precipitation is reduced, but snow

sustains recharge at higher elevations through A

By May, increasing evapotranspiration begins t

deplete soil moisture storage and reduce recharg

to nearly zero.

Evapotranspiration

Precipitation

1960 1965 1970 1975 1980 1985 1990 1995 

WATER YEAR

0

50

5

10

15

20

25

30

35

40

45

INCHES PER YEAR

Recharge

Runoff

Figure 7. Annual mean components of the basinwide water budget, estimated using the Deep Percolation Model for 

years 1962–97.
23

OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP

-2

7

-1

0

1

2

3

4

5

6

INCHES PER MONTH

Precipitation

Runoff

Recharge

Evapotranspiration

Soil moisture change

Snowpack change

Potential evapotranspiration

Figure 8. Mean monthly components of the basinwide water budget, estimated using the Deep Percolation Model for water

years 1962–97.

Canal Leakage

There are approximately 720 miles of canals and

laterals that carry water diverted from the Deschutes

and Crooked Rivers to more than 160,000 acres of

irrigated lands in the basin. Many of the canals are cut

into young basaltic lava that is blocky and highly

fractured; these canals lose large quantities of water.

Most of the leakage percolates to the water table and

is a significant source of ground-water recharge in the

irrigated parts of the basin (fig. 9).

Canal leakage was estimated for the 1994 irrigation season (May–September) using several sources

of information, including: (1) diversions into canals

measured at gaging stations operated by the OWRD,

(2) estimates of irrigated acreage and crop-water

applications from satellite imagery, (3) estimates of

canal leakage rates from ponding experiments and

surveys of canal-bottom geology by BOR (Bureau

of Reclamation, 1991a, 1991b), and (4) estimates of

irrigation efficiency by BOR (Bureau of Reclamation,

1993).

The 1994 canal leakage volume was calculated

as the residual of the volume of water diverted into

canals minus the volume of water delivered to farms.

The areal distribution of canal leakage in the main

canals and laterals was estimated on the basis of

information on canal-bottom geology and ponding

experiments.

To determine the on-farm deliveries from each

canal in 1994, it was necessary to estimate the

irrigated acres within each canal service area, the

amount of water actually needed for the crops to grow

(crop-water requirement), and the average irrigation

efficiency within the canal service area. The actual

crop-water application is equal to the crop-water

requirement divided by the irrigation efficiency. For

example, if the crop-water requirement were 2.0 ft/yr

(feet per year) and the irrigation efficiency were 0.50,

the crop-water application would be 4.0 ft/yr.

Satellite imagery was used to map 164,000

acres of irrigated croplands in the basin in 1994 and

classify them according to the relative magnitude

of crop-water requirements. The three classifications

used were low, medium, and high water requirement

crops. Of the total irrigated acreage, low water

requirement crops made up 33,000 acres, medium

water requirement crops made up 24,000 acres, and

high water requirement crops made up 107,000 acres.
26

Water-rights information from the OWRD was used to

determine that ground water was the source of irrigation to approximately 13,000 acres, with surface water

supplying the remaining 151,000 acres.

The water requirement for each crop classification was estimated based on tables for the region

(Cuenca and others, 1992; Bureau of Reclamation,

1995). County crop census data (Oregon State University, Extension Service, written commun., 1996) was

used to weight the crop-water requirements to reflect

the variability of crops grown in different parts of the

basin. Climatic variability was accounted for by dividing the study area into northern and southern regions

and applying appropriate crop-water requirements to

irrigated lands in each region. The boundary between

the regions coincides with the Deschutes–Jefferson

County line (fig. 1). The low water requirement crop

classification contained mostly fallow land; therefore,

the water requirement was assumed to be zero for

these areas. In 1994, medium water requirement crops

were assumed to need 1.5 acre-feet per acre in the

northern region and 1.7 ft in the southern region, while

high water requirement crops were assumed to need

2.7 ft in the northern region and 2.4 ft in the southern

region.

Irrigation efficiency depends primarily on the

method used to apply the irrigation water. Sprinkler

irrigation is the most efficient method and typically

results in efficiencies of 75 to 90 percent. Flood

irrigation is the least efficient and efficiencies of

35 to 50 percent are typical (U.S. Department of

Agriculture, 1993). Irrigation efficiencies for each

canal service area were estimated based on BOR

studies in the basin (Bureau of Reclamation, 1993)

and from interviews of local irrigation district and

extension service personnel.

The total irrigation-water deliveries to farms

within each canal service area, Ic, in acre-feet per year,

were calculated:

Ic = (Ah × Ch / Ec) + (Am × Cm / Ec)

where,

Ah and Am are the areas of high and medium

water-use crops, in acres,

Ch and Cm are the crop-water requirements

for high and medium water-use crops,

in feet per year, and

Ec is the average irrigation efficiency for

the canal service area, in decimal percent.

Total 1994 diversions, irrigated acreage, o

farm deliveries, and canal leakage are listed for 

major canal in table 4.

Canal leakage rates vary greatly within th

study area depending on the geology of the can

bottom, the degree to which cracks and voids h

been filled by sediment, and the wetted perimet

of the canal. The estimated total leakage within

each canal service area (table 4) was apportione

among the canal and laterals on the basis of

information available from studies by the BOR

(Bureau of Reclamation, 1991a, 1991b, 1993).

The BOR conducted ponding experiments in se

canal reaches and determined leakage rates rang

from 0.64 to 4.20 ft3/d/ft2. This information wa

extrapolated using geologic mapping of the can

bottoms to estimate leakage rates for most of th

main canals and laterals in the study area (fig. 9

The wetted area of each canal reach was calcula

from the average width, depth, and length of th

canal. Leakage rates were multiplied by wetted

area to obtain estimates of leakage from each

canal reach within a canal service area. If the to

leakage did not match the total estimated as the

residual of diversions minus on-farm deliveries

then the leakage rates were adjusted until the to

matched.

In 1994, 356,600 acre-ft, or 490 ft3/s, leak

through canal bottoms to become ground-water

recharge (table 4). This amounted to 46 percent 

770,400 acre-ft (1,060 ft3/s) diverted into canal

the upper Deschutes Basin. Canal leakage for th

period 1905–97 was estimated for the basin assu

that the same proportion (46 percent) of diversi

would be lost each year (fig. 10). Canal leakage

peaked in the late 1950s when mean annual dive

were approximately 940,000 acre-ft (1,300 ft3/s

nearly 435,000 acre-ft (600 ft3/s) was lost to gr

water recharge.

Figure 9 shows the distribution of canal le

in the basin for 1993–95. The highest rates of le

occur in reaches of the North Unit and Pilot Bu

canals immediately east and north of Bend. In t

reaches, canals are cut through highly fractured

blocky basalt and were estimated to lose an aver

more than 20 ft3/s/mi (cubic feet per second per 

during 1993–95.
27

1 Includes only high and medium water-use crops.

Table 4. Canal diversions, irrigated acreage, on-farm deliveries, and canal leakage, by major canal service area,

upper Deschutes Basin, Oregon, 1994

[All values in acre-feet unless otherwise noted; ft/yr, feet per year; --- not applicable.]

AB C D E F

Canal

Canal

diversions

Irrigated

area1

(acres)

Mean

crop-water

requirement (ft/yr)

Crop-water

needs

(B × C)

Mean irrigation

efficiency

(percent)

Estimated

deliveries

(D / E)

l

Arnold 26,570 2,310 2.25 5,200 0.50 10,400 

Central Oregon 181,500 22,500 2.37 53,330 .43 124,020 

North Unit 196,700 45,000 2.03 91,350 .94 97,180 

Lone Pine 10,640 2,390 2.13 5,090 .89 5,720 

Ochoco 75,000 16,600 2.12 35,190 .66 53,320 

Peoples 6,500 1,540 2.21 3,400 .66 5,150 

Pilot Butte 165,800 14,800 2.36 34,930 .43 81,230 

Squaw Creek 26,400 5,450 1.50 8,180 .62 13,190 

Tumalo 42,600 4,890 2.31 11,300 .60 18,830 

Swalley 38,700 2,450 2.33 5,710 .51 11,200 

Total 770,410 117,930 --- 253,680 --- 420,240 3

Average --- --- 2.15 --- .60 --- 

On-Farm Losses

Applied irrigation water can be lost to evaporation (from droplets, wetted canopy, soil and water

surfaces), wind drift, runoff, and deep percolation.

All of these losses are considered on-farm losses;

however, the contribution of deep-percolation losses

to ground-water recharge was the part of the loss of

direct interest to this study. On-farm losses are directly

correlated with irrigation efficiency. Irrigation efficiency is the ratio of the depth of irrigation water used

by the plant to the depth of irrigation water applied,

expressed as a percentage. As shown in table 4,

estimated mean irrigation efficiencies in the study

area vary from 43 percent in areas where flooding is

the primary method of application to 94 percent where

sprinklers are the primary method.

Literature values were used to estimate losses to

evaporation, wind drift, and runoff. The percentage

of applied irrigation water lost to these sources is

highly variable and dependent on individual watermanagement practices and soil and climatic conditions. A maximum of 20 percent was assumed to be

lost to these sources throughout the study area (

Department of Agriculture, 1993). For example, 

the irrigation efficiency is 60 percent (60 percen

the applied water is used by the plant), of the re

ing 40 percent of applied water, 20 percent is as

to be lost to evaporation, wind drift, and runoff, 

20 percent is assumed to be lost to deep percola

In areas of sprinkler irrigation with efficiencies 

94 percent, only 6 percent of applied water is lo

(mostly to evaporation and wind drift), and no w

is assumed to be lost to deep percolation.

Mean annual recharge (1993–95) from de

percolation of on-farm losses was only about

49,000 acre-ft (68 ft3/s) (fig. 9). The service are

the North Unit canal is almost entirely irrigated 

sprinkler; therefore, no recharge from on-farm l

were estimated in this area. In other areas, wher

mixture of flood and sprinkler irrigation is used

5 in./yr of recharge occurs from on-farm losses

where flood irrigation is the predominant irriga

method receive recharge of up to 10 in./yr from 

farm losses.
28

North Unit canal diversions

North Canal diversions

All other diversions

Central Oregon Canal diversion

Total canal leakage

North Unit 

(295)

YEAR

1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000

0

1,400

100

200

300

400

500

600

700

800

900

1,000

1,100

1,200

1,300

ANNUAL MEAN DIVERSION OR CANAL LEAKAGE, IN CUBIC FEET PER SECOND

Swalley (53.1)

Arnold (47.9)

Deschutes County Municipal Irrigation District (37.3)

Ochoco Feed (32.5)

Squaw Creek (44.6)

Tumalo Creek (40.6)

Columbia Southern (25.8)

Central 

Oregon 

(242)

North Canal (236)

Figure 10. Annual canal diversions and estimated annual mean canal leakage in the upper Deschutes Basin, Oregon,

1905–97. (Mean annual discharge, in cubic feet per second, is shown in parentheses for the period of record for each

diversion.)

Stream Leakage

Where the elevation of a stream is above that

of the water table in adjacent aquifers, water can leak

from the stream to the underlying strata and recharge

the ground-water system. Such streams are termed

losing streams. Conversely, in areas where the stream

elevation is below that of adjacent aquifers, ground

water can discharge to streams, increasing streamflow.

Such streams are termed gaining streams.

In this study, ground-water flow from and to

streams was estimated using data from a variety of

sources. The primary sources of information were

sets of streamflow measurements known as seepage

runs. A seepage run consists of a series of streamflow

measurements taken a few to several miles apart along

a stream over a short enough period that temporal

variations in streamflow are minimal. Tributary inflow

and diversions are measured as well. Any temporal

changes in streamflow occurring during the measurement period also are measured or otherwise accounted

for. Seepage runs provide a snapshot of the rate and

distribution of ground-water inflow to, or leakage

from, a stream; single seepage runs, however, do not

provide information on temporal variations in stream

gains and losses. Seepage runs were conducted along

all major streams in the upper Deschutes Basin by

OWRD, and multiple runs were conducted on certain

streams. Data from the seepage runs were provided by

Kyle Gorman, OWRD (written commun., 1994, 1995,

1996) and are presented in table 5.

The methods used to measure streamflow have

an inherent error of plus or minus 5 percent under

good measurement conditions. Therefore, streamflow

variations of less than 5 percent measured between

two points during a seepage run may represent

measurement error and not an actual gain or loss.

However, if the sum of such small gains or losses

along a reach exceeds the likely measurement error, it

is reasonable to assume there is an actual gain or loss.

Data from stream-gaging stations also were

useful in estimating the amount of ground water

discharging to or leaking from streams. Because

stream gages operate continuously, they can provide

information on temporal changes in gains and losses.
29

Most stream-gage data used in this section and the

following section on ground-water discharge were

from the USGS National Water Information System

(NWIS). Additional data were obtained from published compilations (U.S. Geological Survey, 1958;

Oregon Water Resources Department, 1965). The

locations of gaging stations used in this report are

shown in figure 11, and the station numbers and names

are listed in table 6. Some statistical summaries were

taken from Moffatt and others (1990). Data from

OWRD gages and irrigation diversions were provided

by the OWRD (Kyle Gorman, written commun., 1998,

1999, 2000). Estimated stream gains and losses are

presented in table 7 and shown graphically along with

selected stream-gage locations in figure 12. Unless

otherwise noted, the gain and loss rates in table 7 are

assumed to represent average conditions.

In the upper Deschutes Basin, losing streams are

much less common than gaining streams (fig. 12). The

conditions required for losing streams, a water-table

elevation below the stream elevation, occur much less

commonly than the conditions required for gaining

streams.

The rates of water loss from losing streams are

usually much less than the rates of ground-water

inflow to gaining reaches (fig. 12) because of differences in the ways water enters and leaves streams.

In the upper Deschutes Basin, water typically enters

streams from springs issuing from highly fractured

lava or coarse sedimentary deposits like sands and

gravels. These springs commonly occur above river

level (Ferns and others, 1996), and there is no mechanism by which the fractures or other openings through

which the water emerges can be effectively blocked.

The fractures and openings through which water leaks

from losing streams, in contrast, are much more easily

blocked and sealed. Streams typically carry sediment

suspended in the water column and along the bottom.

Over long periods of time, these materials can

infiltrate the openings and essentially seal them,

greatly reducing the permeability of the streambed.

This process is likely particularly important in

streams, such as those in most of the Deschutes Basin,

that flow in canyons and do not meander and, therefore, do not periodically establish new channels. Irrigation canals lose more water than streams over

a given length. This is because canals are much

younger features and have had much less time to

be sealed by sediment, and possibly because canal

water typically carries very little suspended sediment.

Even though the amount of water lost from stre

the ground-water system is only a fraction of th

amount that flows from the ground-water system 

streams, stream leakage is still an important sou

recharge in certain areas.

Leakage from streams, lakes, and reservo

recharges the ground-water system in some are

the southern part of the basin. Some of the high 

such as Hosmer Lake and Elk Lake (fig. 1) are

essentially ground-water fed, and their leakage

represents little, if any, net ground-water rechar

Others, such as Sparks and Devils Lakes, are fe

least in part by perennial streams. The net groun

water recharge from these lakes is unknown, bu

of it likely emerges as springflow in the Deschu

River and tributaries above Crane Prairie Reser

Crane Prairie Reservoir also loses water th

leakage to the ground-water system. This is the 

reservoir in the southern part of the basin for w

sufficient gages have been operated to allow a g

estimate of seepage losses. The average loss fro

Crane Prairie Reservoir between 1939 and 1950 

computed to be 60,000 acre-ft/yr, or about 83 ft

(U.S. Geological Survey, 1958). A more detaile

analysis indicated that the leakage ranges from 

30 to 135 ft3/s, depending on the stage of the re

(Robert F. Main, OWRD, written commun., 199

Some of this loss probably returns to the Desch

River through springs within about 3 or 4 miles 

Crane Prairie Dam, along what is now an arm o

Wickiup Reservoir. It is probable, however, that 

of this water contributes to the regional ground-

flow system.

The water budget of Wickiup Reservoir is 

as well understood as that of Crane Prairie Rese

Although the major streams entering Wickiup

Reservoir are gaged, there is substantial spring 

into the western parts of the reservoir along the

Deschutes River and Davis Creek. A compariso

annual mean gaged inflow and outflow from W

Reservoir from 1939 to 1991 showed that annua

net spring flow into the reservoir from the west 

from 308 to 730 ft3/s and averaged 486 ft3/s. Th

value does not include evaporation, which is co

ered negligible. This inflow rate varies with clim

conditions and apparently with the stage-depen

losses from Crane Prairie Reservoir (Bellinger, 

Although there is net inflow to the reservoir, the

seepage from the reservoir as well. Sinkholes d

periodically, into which large amounts of water 
30

Table 5. Gain/loss measurements of major streams obtained from Oregon Water Resources Department seepage runs, upper Desch[Q, discharge in cubic feet per second at the measurement site; Trib Q, discharge in cubic feet per second of a tributary entering the stream of interest; Seepage, calcubetween the measurement site and the upstream measurement site (corrected for tributary inflow), negative value indicates a loss of water to the aquifer; USGS, U.S. 

Site River mile Date Q Trib. Q Seepage Date Q Trib. Q Seepage 

Little Deschutes River

Cow Camp 86.0 10/10/95 19.7 -- -- -- -- -- --Highway 58 80.0 10/10/95 31.5 -- 11.8 -- -- -- --Forest Service Road 71.0 10/10/95 28.9 -- -2.6 -- -- -- --Above Gilchrist Pond 64.5 10/10/95 26.9 -- -2.0 10/9/96 32.4 -- --Above Crescent Creek 57.5 10/10/95 15.9 -- -11.0 10/9/96 18.0 -- -14.4Wagon Trail Ranch 43.0 10/10/95 50.4 32.2 2.3 -- -- -- -- Road Crossing 33.5 10/10/95 53.3 -- 2.9 -- -- -- --

(off 6th St. West of La Pine)

Little Deschutes near La Pine 26.7 10/10/95 53.3 -- 0.0 10/9/96 54.7 -- --

(USGS gaging station 14063000)

State Recreation Road 13.7 10/10/95 55.9 -- 2.6 10/9/96 57.7 -- 3.0South Century Drive 5.5 10/10/95 59.2 -- 3.3 10/9/96 59.9 -- 2.2Above Mouth at Crosswater 1.4 10/10/95 57.4 -- -1.8 10/9/96 57.0 -- -2.9

Crescent Creek

Below Crescent Lake 30 10/10/95 5 -- -- -- -- -- --Highway 58 crossing 18.5 10/10/95 33.7 10 18.7 -- -- -- -- Above Mouth 2.2 10/10/95 32.2 -- -1.5 -- -- -- --

Fall River

Near headwaters 9.0 2/21/96 18.3 -- 18.3 -- -- -- --Near La Pine 5.0 2/21/96 119 -- 100.7 -- -- -- --

(USGS gaging station 14057500)

Near mouth 0.4 2/21/96 112 -- -7.0 -- -- -- --

Upper Deschutes River

Below Wickiup Dam 226.7 2/21/96 128 -- -- -- -- -- --

(USGS gaging station 14056500)

Pringle Falls 217.6 2/21/96 126 -- -2.0 -- -- -- --La Pine State Park 208.6 2/21/96 132 -- 6.0 -- -- -- --General Patch Bridge 199.7 2/21/96 268 112 24.0 -- -- -- --Harper’s Bridge 191.7 2/21/96 758 544 -54.0 -- -- -- -- Benham Falls 181.4 2/21/96 1,047 -- 289.0 -- -- -- -- 

(USGS gaging station 14064500)

Indian Ford Creek

Black Butte Ranch Weir 10.7 2/5/92 5.86 -- 5.86 4/23/92 6.42 -- 6.42Willows Ranch Diversion 8.0 2/5/92 4.31 -- -1.55 4/23/92 4.62 -- -1.8Willows Ranch 3.6 2/5/92 4.43 -- 0.1 4/23/92 3.15 -- -1.5Camp Polk Road 2.1 2/5/92 3.02 -- -1.4 4/23/92 2.94 -- -0.2Sisters Airport 1.3 2/5/92 0.01 -- -3.0 4/23/92 0.47 -- -2.5Barclay Road 0.8 2/5/92 0.00 -- 0.0 4/23/92 0.00 -- -0.5Confluence with Squaw Creek 0.0 2/5/92 0.00 -- 0.0 4/23/92 0.00 -- 0.0
31

Table 5. Gain/loss measurements of major streams obtained from Oregon Water Resources Department seepage runs, upper Desch[Q, discharge in cubic feet per second at the measurement site; Trib Q, discharge in cubic feet per second of a tributary entering the stream of interest; Seepage, calcubetween the measurement site and the upstream measurement site (corrected for tributary inflow), negative value indicates a loss of water to the aquifer; USGS, U.S. 

Site River mile Date Q Trib. Q Seepage Date Q Trib. Q Seepage 

Lower Squaw Creek

Brooks-Scanlon Logging Road 22 4/13/94 0.00 -- -- -- -- -- --Near Highway 20 Crossing 19 4/13/94 0.00 -- -- -- -- -- --Camp Polk Road Crossing 16.5 4/13/94 6.61 -- 6.6 -- -- -- --Near Henkle Butte 14.7 4/13/94 7.30 -- 0.7 -- -- -- --Below Squaw Creek Estates 9.9 4/13/94 6.46 -- -0.8 -- -- -- --Forest Road 6360 Crossing 5.5 4/13/94 6.61 -- 0.2 -- -- -- --Above Alder Springs 1.7 4/13/94 7.46 -- 0.9 -- -- -- --Below Alder Springs 1.05 4/13/94 26.50 -- 19.0 -- -- -- --

Middle Deschutes River

Deschutes below Bend 164.3 5/11/92 29.8 -- -- 5/16/94 29.0 -- --

(USGS gaging station 14070500)

Below mouth of Tumalo Creek 160.2 5/11/92 37.1 7.3 0.0 5/16/94 31.2 2.2 0.0 Tumalo State Park 158.8 5/11/92 39.7 -- 2.6 5/16/94 42.3 -- 11.1Deschutes River Ranch 154.5 5/11/92 43.8 -- 4.1 5/16/94 43.7 -- 1.4Above Eagle Crest 146.8 5/11/92 -- -- -- 5/16/94 34.8 -- -8.9Cline Falls State Park 145.3 5/11/92 56.0 -- 12.2 5/16/94 45.1 -- 10.3Crestridge Estates 143.2 5/11/92 -- -- -- 5/16/94 35.2 -- -9.9Tethero Road crossing 141.2 5/11/92 32.4 -- -23.6 5/16/94 36.8 -- 1.6Odin Falls Ranch 138.0 5/11/92 -- -- -- 5/16/94 35.5 -- -1.3Below Odin Falls Ranch 137.5 5/11/92 -- -- -- 5/16/94 44.4 -- 8.9Lower Bridge Road crossing 134.0 5/11/92 52.2 -- 19.8 5/16/94 46.0 -- 1.6NW Riffle Road 130.5 5/11/92 67.7 -- 15.5 5/16/94 61.4 -- 15.4Below fishing point near mine cabin 128.7 5/11/92 216 -- 148.3 5/16/94 217 -- 155.6Half mile below Steelhead Falls 127.2 5/11/92 223 -- 7.0 5/16/94 -- -- --River Place below pump house 126.1 5/11/92 207 -- -16.0 5/16/94 -- -- --Sundown Canyon Road 124.9 5/11/92 226 -- 19.0 5/16/94 213 -- -4Scout Camp Trail Road 123.3 5/11/92 365 -- 139.0 5/16/94 341 -- 128.0Below mouth of Squaw Creek 123.0 5/11/92 468 103 0.0 5/16/94 442 101 0.0 Deschutes River near Culver 120.0 5/11/92 480 -- 12.0 5/16/94 467 -- 25.0

(USGS gaging station 14076500)

Lower Crooked River

Crooked River near Terrebonne 27.6 6/22/94 10.5 -- -- -- -- -- --Trail Crossing 20.4 6/22/94 23.6 -- 13.1 -- -- -- --At Osborne Canyon 13.8 6/22/94 93.5 -- 69.9 -- -- -- --Crooked River below Opal Springs 6.7 6/22/94 1,100 -- 1,006.5 -- -- -- --

(USGS gaging station 14087400)
33

1 Oregon Water Resources Department (1965).

2 Kyle Gorman, OWRD, written commun. (1999).

3 U.S. Geological Survey (1958).

4 Hubbard and others (2000).

Table 6.Station numbers, names, and mean annual flow for selected gaging stations in the upper Deschutes Basin, O

[All data are from Moffatt and others (1990) unless noted; OWRD, Oregon Water Resources Department]

Station number Station name Mean annual flow Period of reco

14050000 Deschutes River below Snow Creek, near La Pine 151 1938 to 1987

14050500 Cultus River above Cultus Creek, near La Pine 63 1923 to 1987

14051000 Cultus Creek above Crane Prairie Reservoir, near La Pine 22 1924 to 1962

14052000 Deer Creek above Crane Prairie Reservoir, near La Pine 7.5 1924 to 1987

14052500 Quinn River near La Pine 24 1938 to 1987

14054500 Browns Creek near La Pine 38 1923 to 1987

14055100 Davis Creek (OWRD gage data)1 191 1939 to 1942

14055500 Odell Creek near Crescent 82 1913 to 1976

14055600 Odell Creek (OWRD gage data, gage several miles

downstream of gage 14055500)2

126 1970 to 1990

14056500 Deschutes River below Wickiup Reservoir, near La Pine 754 1943 to 1987

14057500 Fall River near La Pine 150 1938 to 1987

14061000 Big Marsh Creek near Hoey Ranch, near Crescent 72 1912 to 1958

14063000 Little Deschutes River near La Pine 208 1924 to 1987

14063800 Deschutes River at Peters Ranch (OWRD gage data)1 1,210 1944 to 1953

14064000 Deschutes River at Camp Abbott Bridge (OWRD gage data)1 1,478 1944 to 1953

14064500 Deschutes River at Benham Falls, near Bend 1,480 1944 to 1987

14066000 Deschutes River below Lava Island, near Bend 1,380 1943 to 1965

14070500 Deschutes River below Bend 377 1957 to 1987

14073001 Tumalo Creek near Bend 101 1924 to 1987

14075000 Squaw Creek near Sisters 105 1906 to 1987

14076500 Deschutes River near Culver 929 1953 to 1987

14087400 Crooked River below Opal Springs, near Culver 1,610 1962 to 1987

14087500 Crooked River near Culver 1,560 1920 to 1960

14088000 Lake Creek near Sisters 52 1918 to 1987

14088500 Metolius River at Allingham Ranger Station,

near Sisters3

376 1911 to 1912

14090350 Jefferson Creek near Camp Sherman4 94.9 1984 to 1999

14090400 Whitewater River near Camp Sherman4 86.6 1983 to 1999

14091500 Metolius River near Grandview 1,500 1912 to 1987

14092500 Deschutes River near Madras 4,750 1964 to 1987
34

Table 7. Estimated stream gains and losses due to ground-water exchange, upper Deschutes Basin, Oregon[RM, river mile; ft3/s, cubic feet per second; OWRD, Oregon Water Resources Department; USGS, U.S. Geological Survey; Res., reservoir; NW, northwest; OSU, Or

Stream Name

Reach

(river mile)

Estimated

gain (+)

or loss (-)

(ft3/s) Data source 

Little Deschutes River Entire drainage above Highway 58, RM 80 31.5 OWRD measurements 10/95 Includes HemLittle Deschutes River Highway 58 to above Crescent Creek,

RM 80 to RM 57.5

-15.6 OWRD measurements 10/95

Little Deschutes River Above Crescent Creek to Crosswater,

RM 57.5 to RM 1.4

9.3 OWRD measurements 10/95

Big Marsh Creek Drainage above gage near Mouth, RM 0.5 21 Statistical summary of gage 14061000

(Moffatt and others, 1990)

Mean Septem

Crescent Creek Crescent Lake outlet to Highway 58,

RM 30 to RM 18.5

18.7 OWRD measurements 10/95 Includes inflo

Crescent Creek Highway 58 to above mouth,

RM 18.5 to RM 2.2

-1.5 OWRD measurements 10/95

Paulina Creek Paulina Lake outlet to Road 21,

RM 13 to RM 5.2

-1.7 to -6.1 Morgan and others (1997)

Odell Lake Above gage at lake outlet 41 Statistical summary of gage 14055500

(Moffatt and others, 1990)

Mean Septem

Odell Creek Odell Lake outlet to OWRD gage 41 USGS and OWRD gage data for

stations 14055500 and 14055600

Period of over

Davis Creek Upstream from RM 3 191 OWRD gage data for station 14055100

(1938–43), OWRD miscellaneousmeasurements 1978–94

Entire flow fro

Cultus River Above Cultus Creek 63 Statistical summary of gage 14050500

(Moffatt and others 1990)

Mean annual 

Deschutes River Above Crane Prairie Res. 151 Statistical summary of gage 14050000

(Moffatt and others, 1990)

Mean annual 

Deschutes River Crane Prairie Res. to Wickiup Res. 229 USGS Water-Supply Paper 1318 Based on gage Deschutes River Wickiup Res. to La Pine State Park,

RM 226.7 to RM 208.6

4 OWRD measurements 2/96

Fall River Headwaters springs to gage at RM 5 119 OWRD measurements 2/96 Entire flow froFall River Gage to mouth, RM 5 to RM 0.4 -7 OWRD measurements 2/96Deschutes River Near Fall River, RM 208.6 to RM 199.7 24 OWRD measurements 2/96
35

Deschutes River Peters Ranch to Camp Abbott Bridge,

RM 191.5 to RM 189

271 OWRD gage data for stations

14063800 and 14064000

Period of recoincludes flow 

Deschutes River Camp Abbott Bridge to Benham Falls,

RM 189 to RM 181.4

-24 OWRD and USGS gage data for

stations 14064000 and 14064500

Period of reco

Deschutes River Benham Falls to below Bend,

RM 181.4 to 164.4

-89 USGS and OWRD gage data

for the river and diversions

Period of reco

Tumalo Creek Entire drainage above gage at RM 3.1 68 Statistical summary of gage 14073001

(Moffatt and others, 1990)

Mean August–1987, does no

Tumalo Creek RM 2.3 to RM 0.3 -0.24 OWRD measurements 8/94 MeasurementDeschutes River Below Bend to Odin Falls Ranch,

RM 164.4 to RM 138.0

6.5 OWRD measurements 5/94 Gain may dec

may be irrigat

Deschutes River Odin Falls Ranch to NW Riffle Road,

RM 138.0 to RM 130.5

17.0 OWRD measurements 5/94 Gain may be i

Deschutes River Riffle Road to Culver gage,

RM 130.5 to RM 120.0

305 OWRD measurements 5/94

Indian Ford Creek Upstream from RM 10.7 at Black Butte

Ranch

6.1 OWRD measurements 2/94–4/94

Indian Ford Creek Black Butte Ranch to mouth,

RM 10.7 to RM 0.8

-6.1 OWRD measurements 2/94–4/94 Stream dry at 

Squaw Creek Entire drainage above gage at RM 26.8 65 Statistical summary of gage 14075000

(Moffatt and others 1990)

Mean Septemmay be influe

Squaw Creek Near McKinney Butte,

RM 19 to RM 16.5

6.6 OWRD measurements 4/94 Discharge fro

Squaw Creek McKinney Butte to Alder Springs,

RM 16.5 to RM 1.7

0.85 OWRD measurements 4/94

Squaw Creek Alder Springs to confluence

RM 1.7 to RM 0

94 OWRD measurements 4/94 and 5/94

(at mouth)

Crooked River Terrebonne to Trail Crossing,

RM 27.6 to 20.4

13.1 OWRD measurements 6/94

Crooked River Trail Crossing to Osborne Canyon,

RM 20.4 to 13.8

70 OWRD measurements 6/94

Table 7. Estimated stream gains and losses due to ground-water exchange, upper Deschutes Basin, Oregon—Continued

[RM, river mile; ft3/s, cubic feet per second; OWRD, Oregon Water Resources Department; USGS, U.S. Geological Survey; Res., reservoir; NW, northwest; OSU, Or

Stream Name

Reach

(river mile)

Estimated

gain (+)

or loss (-)

(ft3/s) Data source 
36

Crooked River Osborne Canyon to Opal Springs gage,

RM 13.8 to RM 6.7

1,006 OWRD measurements 6/94

Metolius River Headwaters to Allingham Ranger Station

(gage site) at RM 38.1

257 Alexander and others (1987, p. 215);

data for gage 14088500(USGS Water-Supply Paper 1318)

Estimated by periods: 9/85 1911 to 1917.

Suttle Lake Lake above gage at outlet 31 Statistical summary of gage 14088000

(Moffatt and others, 1990)

Mean Septem

Lake Creek Suttle Lake to mouth 36 Alexander and others (1987, p. 215)

and Lake Creek gage data

9/85 measuremof Metolius R

First Creek Upper part of drainage 1.5 OWRD measurements 1992–94Jack Creek Upper part of drainage 46 OWRD measurements 1992–94Canyon Creek Entire drainage above about RM 0.5 60 OWRD measurements 1992–94Abbot Creek Entire drainage above about RM 1.5 12 OWRD measurements 1992–94Candle Creek Entire drainage above about RM 2 73 OWRD measurements 1992–94Metolius River Allingham Ranger Station (RM 38.1) to

gage near Grandview (RM 13.6) includinglower parts of tributary drainages

724 OWRD measurements 1992–94,

USGS gage data

Gain based on and mean AugMost inflow o(RM 28.8)

Lake Billy Chinook Reservoir encompassing confluence of the

Deschutes, Crooked, and Metolius Rivers

379–461 USGS gage data and

Bolke and Laenen (1989)

Figure uncertaEvaporation is 

based on 1997 Agricultural E

Deschutes River Round Butte Dam to Lake Simtustus,

RM 109.9 to RM 108.5

200 Bolke and Laenen (1989)

Lake Simtustus Reservoir on the Deschutes River

extending from RM 108.5 to RM 102.8

51 Bolke and Laenen (1989) Figure does n

Deschutes River Pelton Dam to Regulator Dam,

RM 102.8 to RM 100.1

80 Bolke and Laenen (1989)

Deschutes River Regulator Dam to below Campbell Creek,

RM 100.1 to RM 97.2

53 Bolke and Laenen (1989)

Deschutes River Below Campbell Creek to Dry Creek,

RM 97.2 to RM 91.8

28 Bolke and Laenen (1989) No significant 

in study area

Table 7. Estimated stream gains and losses due to ground-water exchange, upper Deschutes Basin, Oregon—Continued

[RM, river mile; ft3/s, cubic feet per second; OWRD, Oregon Water Resources Department; USGS, U.S. Geological Survey; Res., reservoir; NW, northwest; OSU, Or

Stream Name

Reach

(river mile)

Estimated

gain (+)

or loss (-)

(ft3/s) Data source 
38

Sinkholes apparently have been less of a problem

since the early 1960s (Bellinger, 1994). The average

rate of seepage from Wickiup Reservoir is unknown,

but it is probably not more than a few tens of cubic feet

per second.

Seepage runs indicate some losses along the

Little Deschutes River as it flows through the La Pine

subbasin (table 5). Most of the measured losses are

small, 1 to 3 ft3/s, and are within the measurement

error of the 30 to 60 ft3/s streamflow rates. Measured

losses between Gilchrist and Crescent Creek, ranging

from 11 to 14.4 ft3/s, are sufficiently large with respect

to measurement error to be considered meaningful.

The Little Deschutes River crosses lava flows of

Crescent Butte Volcano along this reach and it is likely

that water is being lost into permeable lava. Much

of this water likely returns to the river in gaining

reaches not far downstream. A seepage run on

Crescent Creek, a tributary to the Little Deschutes

River, indicated a 1.5 ft3/s loss in the lower 18 miles.

This loss is small compared to the flow, approximately

33 ft3/s, and is within the measurement error.

Paulina Creek, a tributary to the Little Deschutes

River that flows down the west flank of Newberry

Volcano, had measured net losses of approximately

2 to 6 ft3/s between river mile 13, at its source at the

outlet of Paulina Lake, and river mile 5.2, where it

flows onto the floor of the La Pine subbasin (M

and others, 1997). This loss accounted for roug

to 40 percent of the flow of Paulina Creek at the 

the seepage runs were made.

Seepage runs indicate that, with the excep

of the reservoirs discussed previously, the Desc

River has no significant losing reaches upstream

of its confluence with the Little Deschutes Rive

Downstream from the confluence, gaging-statio

data indicate significant losses occur along the r

extending from the community of Sunriver dow

stream to Bend. Comparison of flow measured 

gage operated from 1945 to 1953 at the Camp A

Bridge with the flow at the Benham Falls gage 

10 miles downstream indicates that this reach o

river lost an average of about 24 ft3/s during tha

period (Oregon Water Resources Department, 1

The loss, as calculated using monthly mean flow

variable and weakly correlated with flow (corre

coefficient = 0.40).

The Deschutes River loses an average 83 

between Benham Falls and the gage site below

Lava Island about 7.5 miles downstream, based 

the period of record from 1945 to 1965. The los

in flow along this reach ranged from −10 ft3/s (

slight gain) to 236 ft3/s and is fairly well correl

with flow (correlation coefficient = 0.74) (fig. 1

-50

0

50

100

150

200

250

0 500 1000 1500 2000 2500 3000 

MONTHLY MEAN FLOW AT BENHAM FALLS, IN CUBIC FEET PER SECOND

LOSS BETWEEN BENHAM FALLS AND LAVA ISLAND, 

IN CUBIC FEET PER SECOND

Figure 13. Relation between monthly mean losses along the Deschutes River between Benham Falls and Lava Isl

and flow at Benham Falls.
39

The wide range of these values is likely due to measurement error of the stream gages and of the gage

on a diversion used in the loss calculation. The rate

of leakage in this reach far exceeds that of any other

losing stream reach in the upper Deschutes Basin. The

leakage in this area is likely into very young, highly

permeable lava flows from Lava Butte that diverted the

river and now form much of the east bank and some

of the falls along this reach. Stream losses between

Camp Abbott Bridge and Lava Island far exceed losses

anywhere else in the upper Deschutes Basin and are an

important source of recharge.

USGS and OWRD stream-gage data from 1945

to 1965 indicate that average stream losses between

the gage below Lava Island and the gage below Bend

are small, about 4.0 ft3/s. The difference in flow along

this reach ranged from a 68 ft3/s gain to a 72 ft3/s loss,

and shows no correlation with flow. The wide range in

values is likely due to measurement error of the stream

gages and of the gages on five diversions used in the

calculations.

Calculated losses along the two reaches of the

Deschutes River described above, which total 87 ft3/s,

are based on a period of record from 1945 to 1965.

Losses along the two separate reaches after 1965

cannot be calculated because the gage below Lava

Island ceased operation. Losses can be calculated,

however, for the entire reach from Benham Falls to

Bend for a much longer period. The average loss

between Benham Falls and Bend, based on monthly

mean flows from 1945 to 1995, is 89 ft3/s. This agrees

favorably with the sum of losses calculated for the

subreaches for the shorter period of record.

Information on stream losses along the

Deschutes River from Bend downstream to Lower

Bridge is from OWRD seepage runs (Kyle Gorman,

OWRD, written commun., 1995) (table 5); gage data

are insufficient for evaluating losses along this reach.

Seepage runs indicate that there are two areas between

Bend and Lower Bridge where the Deschutes may

lose a small amount of water (table 5). These areas

are between river miles 154.5 and 146.8, near Awbrey

Falls, and between river miles 145.3 and 143.2, near

Cline Falls. Losses in both these areas are about

10 ft3/s, and were measured when flows ranged from

30 to 50 ft3/s. Not far downstream from both of these

losing reaches, the river gains comparable amounts

of water, implying that water lost from the river along

this section apparently returns to the surface not far

downstream. These seepage runs were done during

periods of very low streamflow and may not refl

losses at higher flow rates. However, gage data 

upstream between Lava Island and Bend sugge

losses may not be flow dependent along this rea

There are no significant losses from the Deschu

River downstream of Lower Bridge.

Stream losses also were measured along I

Ford Creek (table 5). A series of seepage measu

ments taken by OWRD during the winter month

1992 indicate that Indian Ford Creek lost its en

flow (approximately 6 ft3/s) between the Black 

Ranch springs, where it originates, and its confl

with Squaw Creek.

No other streams measured in the upper D

chutes Basin showed significant losses. The low

sections of Tumalo and Squaw Creeks showed 

minor losses of less than 1 ft3/s when measured 

low flow conditions. Possible losses during high

flow conditions are not known.

Drainage Wells

Storm runoff in urban areas of the upper D

chutes Basin is often disposed of through drain

wells. Drainage wells in this report include both

drilled disposal wells and larger diameter, but

shallower, drywells, which are usually dug. Run

disposed of in drainage wells is routed directly 

permeable rock beneath the land surface, bypas

the soil zone from which a certain amount of the 

would normally be returned to the atmosphere th

evaporation or transpiration by plants. Once rou

permeable rock beneath the soil, the runoff perc

downward to recharge the ground-water system

Although runoff disposed of through drain

wells represents a source of ground-water recha

the volume of water is very small relative to oth

sources of recharge in urban areas, such as cana

age, and minuscule compared to the entire grou

water flow budget. To illustrate this, estimates o

the amount of ground-water recharge through dr

wells in Bend and Redmond are presented in th

section.

Engineering maps provided by the city of 

in 1994 show approximately 1,175 drainage we

used for street drains in the city. This number d

not include drainage wells on private property, 

their distribution is taken to represent the area o

which runoff is handled in this manner. There a

163 quarter-quarter sections (40-acre tracts) wit
40

least 1 and as many as 30 drainage wells. The quarterquarter sections with at least one drainage well

compose a total area of just over 10 mi2. To estimate

the amount of ground-water recharge from drainage

wells, it is necessary to estimate the fraction of the

total precipitation that is routed to them.

Runoff routed to drainage wells is that which

falls on impervious surfaces and cannot infiltrate

the soil naturally. Roofs, driveways, parking lots,

and streets are examples of impervious surfaces. The

amount of impervious surface relative to the total land

area varies with land-use type. Commercial areas, with

large roofed structures and expansive parking lots, can

be 85 percent impervious (Snyder and others, 1994).

Impervious surfaces in residential areas, in contrast,

range from 20 percent of the land area, for large lots

where yards are big relative to structures and driveways, to 65 percent for small lots (Soil Conservation

Service, 1975). A value of 35 percent impervious

surface was used for calculations for Bend, based on

mapped impervious areas for dominantly residential

areas in Portland, Oregon, and Vancouver, Washington

(Laenen, 1980, table 1).

Not all of the precipitation that falls on impervious surfaces runs off to drainage wells. A certain

amount is evaporated from wetted surfaces and

undrained areas such as puddles, and from detention

structures. This is known as detention-storage loss.

In estimating recharge from drainage wells in the

Portland Basin, Snyder and others (1994), using

the work of Laenen (1980), estimated that about

25 percent of the precipitation was evaporated in this

manner, leaving about 75 percent to run off to drainage wells. Because this value was derived using conditions in western Oregon, it may be low for the Bend

area, where conditions are much dryer. A detentionstorage loss of 25 percent is used herein with the

assumption that if it is too conservative, recharge from

drainage wells may be slightly overestimated.

Average recharge from drainage wells in Bend

was estimated assuming that runoff from all impervious surfaces in any quarter-quarter section (40-acre

tract) with at least one drainage well was disposed of

through drainage wells. There are 163 quarter-quarter

sections meeting this criteria, with an aggregate

area of 10.19 mi2. Average precipitation in Bend is

11.70 in./yr (period of record 1961 to 1990) (Oregon

Climate Service, 1999). Using these figures and

assuming that 35 percent of the area is impervious

surface and that 25 percent of the precipitation is lost

through evaporation, the runoff routed to dry w

is approximately 73 million ft3/yr, or about 2.3 

This is not a significant source of recharge whe

pared to canal and stream leakage, which can ex

20 ft3/s/mi near Bend.

Similar calculations were done for Redmo

using maps provided by the city and aerial phot

graphs taken in 1995. A public-facilities map in

there are about 30 quarter-quarter sections with

Redmond in which there is at least one drainage 

with an aggregate area of 1.88 mi2. Analysis of 

aerial photographs suggests that there may be n

idential areas not included in this total, but these 

sent only a small increase in the total area and a

included in the following calculation. Using the 

values as in the analysis for Bend to represent t

percentage of impervious area and evaporative 

and an average annual precipitation of 7.83 inch

(1961–90), total runoff to drainage wells in Red

is estimated to be approximately 9 million ft3/y

about 0.28 ft3/s. As with Bend, this is not a sign

source of recharge.

Similar calculations were not carried out f

other urban areas in the upper Deschutes Basin

Examples from Bend and Redmond, the most u

ized areas, illustrate that runoff to drainage well

an important volumetric component of ground-

recharge.

Although runoff to drainage wells is not v

metrically substantial, it may be significant in te

water quality. Urban runoff can contain contam

such as household pesticides and fertilizers, and 

motive petroleum products. Runoff routed direc

to drainage wells has a direct pathway to the gr

water system, bypassing the soil zone, where na

processes such as filtration, adsorption, and bio

radation may serve to reduce levels of some con

nants.

Interbasin Flow

The final source of recharge to the upper

Deschutes Basin regional ground-water system 

subsurface flow from adjoining basins. In gener

lateral boundaries of the upper Deschutes Basin 

area are considered to be no-flow boundaries. T

are, however, two areas where inflow from adja

areas is probable: along the Cascade Range cre

the Metolius River drainage and in the southeas

part of the study area northeast of Newberry Vo
41

The western boundary of the study area coincides with the topographic crest of the Cascade Range.

It is generally considered a no-flow boundary because

the ground-water divide is assumed to follow the distribution of precipitation, which generally follows the

topography. The isohyetal map of Taylor (1993) shows

that in the area of the Metolius River subbasin, the

region of highest precipitation occurs west of the topographic crest of the Cascade Range, suggesting that the

ground-water divide is also to the west of the topographic divide and that there is likely ground-water

flow eastward across the topographic divide. This

interbasin flow is also indicated by the hydrologic budget of the Metolius River subbasin. Average groundwater discharge to the Metolius River in the study

area above the gage near Grandview is approximately

1,300 ft3/s. The mean annual recharge from precipitation in the Metolius River subbasin above this point in

the study area is estimated to be only about 500 ft3/s.

The difference, 800 ft3/s, almost certainly comes from

subsurface flow from an adjacent basin. The most

plausible source for this additional water is the upper

Santiam and North Santiam River Basins to the west.

South of Bear Creek Butte, through Millican and

the China Hat area, the eastern study-area boundary

does not coincide with either a topographic divide or

a geologic contact. The region east of this area was

not included in the study area because of the lack of

subsurface hydrologic information, very low recharge,

and distance from the areas of primary concern.

Hydraulic-head data, however, indicate there is some

flow across this boundary into the study area from the

southeast. This flux was estimated using a variety of

methods.

The part of the Deschutes Basin east of this

boundary is very dry (10 to 15 in./yr precipitation)

and has a poorly developed drainage system with no

perennial streams. The divide between this part of the

Deschutes Basin and the Fort Rock and Christmas

Lake Basins to the south is poorly defined and

interbasin flow is likely. Miller (1986) states that

flow to the Deschutes Basin from the Fort Rock Basin

“probably exceeds 10,000 acre-ft/yr,” which equals

about 14 ft3/s. Estimates based on the Darcy equation,

using measured head gradients and estimated hydraulic

conductivity and aquifer thickness, suggest that the

flux into the study area may be as high as 100 ft3/s.

Additional estimates were derived using a waterbudget approach. The probable area contributing to the

boundary flux was defined using hydraulic-head maps

from the Deschutes Basin and the Fort Rock Ba

(Miller, 1986). Flux rates were calculated using 

range of recharge values from Newcomb (1953

Miller (1986), and McFarland and Ryals (1991)

Assuming a contributing area of 648 mi2 and re

estimates ranging from 0.5 to 3.0 in./yr, the bou

flux could range from 25 to 145 ft3/s. If recharg

assumed to be 1.0 in./yr in the contributing area 

this boundary flux, the estimated flux rate is abo

50 ft3/s.

GROUND-WATER DISCHARGE

Ground water discharges from aquifers to

streams, to wells, and through evapotranspiratio

Discharge to streams is the principal avenue by 

water leaves the ground-water system. Discharg

occur to discrete springs or as diffuse seepage th

streambeds. Pumping by wells is another avenu

which ground water leaves the ground-water sy

In the Deschutes Basin, discharge to wells repre

small fraction of the total ground-water dischar

Evapotranspiration by plants is the third mecha

considered in this report. Most plant water requ

ments are met by water percolating downward th

the soil before it enters the ground-water system

some areas where the water table is sufficiently 

low to be within the rooting depth of plants, tra

tion can occur directly from the ground-water s

This process represents a very small fraction of 

total ground-water discharge in the basin. Each 

these mechanisms is discussed in more detail in 

following sections.

Ground-Water Discharge to Streams

Discharge to streams is the main avenue b

which water leaves the ground-water system an

one of the major components of the hydrologic b

Ground water discharges to streams in areas wh

stream elevation is lower than the elevation of t

water table in adjacent aquifers. Considerable am

of ground water can discharge to the streams in 

way from regional aquifers with large recharge 

Streams in which the flow increases due to grou

water discharge are termed gaining streams. Th

amount of ground water discharging to streams 

leaking from streams varies geographically and 

time.
42

Understanding the rates and distribution of

ground-water discharge to streams is critical to understanding the ground-water hydrology of an area. The

amount and location of ground-water discharge can be

determined by measuring streamflow at points along

a stream and accounting for tributary inflow and diversions between the points as well as temporal changes

in flow. In general, increases in flow from point to

point downstream that are not due to tributary inflow

are caused by ground water discharging to the stream.

Discharge can occur either at discrete locations such

as springs or as diffused seepage through the streambed.

Stream-gage data can be particularly useful for

estimating ground-water discharge. Gages on springfed streams, such as Fall River, measure ground-water

discharge directly. Data from pairs of gages operated

concurrently along a stream can be compared to

estimate ground-water inflow between the gages

as long as tributary inflow and diversions can be

accounted for. Late summer and early fall flows in

some streams are essentially entirely ground-water

discharge (base flow). Therefore, annual low flows at

certain stream gages can provide reasonable estimates

of ground-water discharge.

Estimates of ground-water discharge to major

streams in the upper Deschutes Basin are provided

in table 7. These estimates are based on seepage runs

and stream-gage data as well as other miscellaneous

measurements. Unless otherwise noted, the values

in table 7 represent approximate long-term average

conditions.

Geographic Distribution of Ground-Water Discharge

to Streams

There are three main settings in the upper Deschutes Basin where substantial amounts of groundwater discharge to streams: the southern part of the

basin in and near the margin of the Cascade Range,

the Metolius Basin adjacent to the Cascade Range, and

the area surrounding the confluence of the Deschutes,

Crooked, and Metolius Rivers extending downstream

to about Pelton Dam (fig. 12). This latter area is

referred to as the “confluence area” in this report.

Ground water constitutes a large proportion of

the flow in many streams in and along the margin of

the Cascade Range in the southern part of the basin

(table 7). Ground water constitutes virtually the entire

flow of some of these streams, such as Fall River. Such

streams are recognized by the presence of source

springs, lack of tributary streams, and flows that are

very constant relative to other streams. Hydrographs

of mean monthly flows (fig. 14) illustrate the differences between streams in which ground water is a

the dominant source and those in which surface runoff is the dominant source. Fall, Cultus, and Quinn

Rivers, and Browns Creek all show relatively little

variation in flow throughout the year indicating that

0

50

100

150

200

250

OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP

MONTH

MEA

N

M

O

N

T

HLY

S

T

REA

MFLOW FO

R

ALL

S

T

REA

M

S

EX

CEPT

T

HE METOLIU

S

RIVER,

IN

C

UBIC FEE

T PER

SECO

N

D

MEA

N

M

O

N

T

HLY

S

T

REA

MFLOW FO

R

METOLIU

S

RIVER,

IN

C

UBIC FEE

T PER

SECO

N

D

Cultus Creek

Deschutes River below Snow Creek

Cultus River

Deer Creek

Quinn River

Browns Creek

Fall River

Big Marsh Creek

Squaw Creek

Metolius River

2,500

2,000

1,500

1,000

500

0

Figure 14. Mean monthly flows of selected nonregulated streams in the upper Deschutes Basin, Oregon.
43

they are not greatly affected by surface runoff and that

ground water provides most of their flow. In contrast,

Squaw, Big Marsh, Cultus, and Deer Creeks, and the

Deschutes River (measured at the gage below Snow

Creek just above Crane Prairie Reservoir) all show

substantial increases in flow during spring due to runoff, indicating that their flow is dominated, or at least

affected, by surface runoff.

Some of these runoff-dominated streams, such

as the Deschutes River, have substantial flow even

during the driest months of the year, indicating that

ground-water discharge constitutes an important part

of the flow. Others, such as Cultus and Deer Creeks,

nearly cease to flow in the driest months of the year,

indicating that ground-water discharge is only a minor

part of their total flow. Temporal variations in groundwater discharge are discussed in more detail in a later

section of the report.

The Metolius River drainage is the second region

of significant ground-water discharge in and along

the margin of the Cascade Range (fig. 12, table 7). The

Metolius River drainage comprises numerous streams

emanating from the Cascade Range, many of which

are spring fed and others that are probably runoff

dominated. The only long-term stream gage on the

Metolius River is low in the drainage just above Lake

Billy Chinook (this gage is officially referred to as

being near Grandview, an abandoned town site).

Although this gage represents a large drainage area

that encompasses both spring-fed and runoffdominated streams, it warrants analysis because of

the large volume of ground water that discharges in

the Metolius River drainage. Two tributary streams,

Jefferson Creek and Whitewater River, carry glacial

runoff from Mt. Jefferson and have late-season flows

not entirely attributable to ground-water discharge.

A hydrograph of the monthly mean flow of the

Metolius River near Grandview from 1922 to 1997

(fig. 15) clearly shows transient runoff events caused

by spring snowmelt and large storms. During the late

summer, however, when surface runoff is minimal, the

flow of the Metolius is largely ground-water discharge.

These late-summer flows are relatively large, reflecting the large amount of ground-water discharge. The

lowest mean monthly flow occurs during October.

The mean October flow of the Metolius River near

Grandview for the period 1912–87 was 1,350 ft3/s

(Moffatt and others, 1990). This amount includes the

flow of Jefferson Creek and Whitewater River, which

may include late-season glacial melt, but the contribution from these streams is relatively small. The mean

October flow of Jefferson Creek was 77 ft3/s during

0

500

1,000

1,500

2,000

2,500

3,000

3,500

1920 1930 1940 1950 1960 1970 1980 1990

YEAR

MONTHLY MEAN STREAMFLOW, IN CUBIC FEET PER SECOND

Monthly mean flow

October mean flow

Figure 15. Monthly mean flow of the Metolius River near Grandview. (The line connecting the October mean flows approximates ground-water discharge.)
44

the period 1984–98 and that of Whitewater River was

53 ft3/s during the period 1983–98. Depending on the

amount of the mean October flow of these streams

that is glacial in origin, the mean October flow of the

Metolius River near Grandview that is derived from

ground-water discharge is between 1,220 and

1,350 ft3/s.

A variety of regional geologic factors controls

the location of ground-water discharge to streams

and springs in and along the margins of the Cascade

Range. Many large spring areas and gaining stream

reaches, such as Fall and Spring Rivers, coincide with

the boundary of the La Pine and Shukash structural

basins. The low-permeability basin-filling sediments

likely divert ground water toward the surface by acting

as an impediment to subsurface flow.

Geologic structure can also influence groundwater discharge in and along the margins of the

Cascade Range. The tremendous amount of ground

water discharging to the upper Metolius River and its

tributaries is undoubtedly due in large part to the major

fault system along the base of Green Ridge (fig. 4).

Green Ridge is a 20-mile long escarpment that marks

the eastern margin of a north-south trending graben

into which the Cascade Range in that area has subsided (Allen, 1966; Priest, 1990). Vertical movement

along this fault system is estimated to be over 3,000 ft

(Conrey, 1985). The fault system may influence

ground-water discharge in two ways. First, elevation

of the valley on the downthrown side of the fault system is anomalously low when compared to surrounding terrane a similar distance from the Cascade Range.

Low-elevation areas commonly are regions of groundwater discharge. Second, the fault itself likely impedes

eastward movement of ground water flowing from the

Cascade Range, forcing ground water to discharge to

the river. The impediment to eastward ground-water

movement could be due to low-permeability crushed

or sheared rock along the fault planes or the juxtaposition of permeable strata on the west side of the

fault system against low-permeability strata on the

east. Analysis of carbon isotope data (James and

others, 1999) suggests that the water discharged from

the Metolius River springs includes a component

of deep regional ground water, implying that there is

vertical permeability locally along the escarpment.

Local geology also affects the location of

ground-water discharge. Many springs occur along

the edges or ends of Quaternary lava flows. Ground

water emerges at these locations because saturated

permeable zones in or at the base of the lava flo

intersect land surface. Some springs, such as th

the upper end of Davis Creek, emerge in buried 

channels at the ends of intracanyon lava flows.

The total average amount of ground water

discharging to streams in and along the margin 

Cascade Range in the study area is estimated to 

approximately 2,600 ft3/s. This includes discha

to streams in the southern part of the study area

the Tumalo and Squaw Creek drainages, and in 

Metolius River drainage (table 7). Approximate

half of this amount discharges in the Metolius R

drainage.

The third major setting in which ground w

discharges to streams is the region around the

confluence of the Deschutes, Crooked, and Met

Rivers and extending downstream to the vicinit

Pelton Dam. Russell (1905, p. 88) provides an e

description of ground-water inflow in this regio

Crooked River at Trail Crossing, at the t

of my visit in early August [1903], had shrunk t

brook of tepid, muddy, and unwholesome wate

across which one could step dry-shod from sto

to stone. Its volume, by estimate, was not mor

than 2 cubic feet per second.... On descending 

canyon about 12 miles lower down its course I 

surprised to find a swift-flowing, clear stream o

cool, delicious water, by estimate 100 feet wid

and 3 feet deep, with a volume of not less than 

cubic feet per second. This remarkable renewa

resuscitation of a stream in an arid land is due 

the inflow of Opal and other similar springs.

Stearns (1931) also recognized the large a

of ground water discharging to streams in the ar

while investigating the geology and hydrology 

the middle Deschutes Basin for potential dam s

Stearns used stream-gage data to conservatively

estimate ground-water inflow to the lower Croo

River between Trail Crossing and the gaging st

near Culver (now under Lake Billy Chinook) to 

950 ft3/s. He also used gage data to estimated g

water inflow to the Deschutes River between Be

and Madras at about 600 ft3/s. These numbers a

generally consistent with modern estimates whe

effects of irrigation development and of Round 

Dam are considered.

Ground-water discharge to the lower Croo

River and middle Deschutes River was estimate

from OWRD seepage runs (fig. 12, table 5). Gr

water discharge to the lower Crooked River bet

Terrebonne and the gage below Opal Springs w

proximately 1,100 ft3/s in June 1994 (fig. 16, ta
45

Most of this inflow entered the Crooked River below

Osborne Canyon, about 7 miles upstream from the

gaging station below Opal Springs. The Deschutes

River gained approximately 400 ft3/s along the

10-mile reach above the gaging station near Culver,

just above Lake Billy Chinook, during seepage

runs in May 1992 and May 1994 (fig. 17, table 5).

About 300 ft3/s of this gain was from ground-water

discharge directly to the Deschutes River, and the

remaining 100 ft3/s was mostly from ground-water

0

200

400

600

800

1,000

1,200

30 25 20 15 10 5

RIVER MILE

STREAMFLOW, IN CUBIC FEET PER SECOND

Near

Terrebonne

Trail

Crossing

Osborne

Canyon

Opal

Springs

Figure 16. Gain in flow of the lower Crooked River,

Oregon, due to ground-water discharge between

river miles 27 and 7, July 1994.

discharge to lower Squaw Creek near its conflu

with the Deschutes River. A seepage run made 

Squaw Creek in April 1994, combined with dat

the seepage run along the Deschutes River a mo

later, showed Squaw Creek gaining approximat

94 ft3/s from springflow in the lower 1.7 miles f

Alder Springs to the confluence (table 7).

The ground-water discharge estimates fro

seepage runs on the lower Crooked River, Desc

River, and Squaw Creek are probably conservat

estimates of long-term mean annual ground-wa

discharge. The seepage runs were conducted af

period of several relatively dry years. The mont

mean streamflows for the months during which 

seepage runs were conducted were low compar

to the long-term mean monthly flows (Hubbard 

others, 1993, 1995). Temporal variations in gro

water discharge are discussed in a later section.

Ground-water inflow to Lake Billy Chino

estimated from stream-gaging-station data, is ro

420 ft3/s (the middle of the range in table 7). Fr

Round Butte Dam downstream to Dry Creek at 

mile 91.8 (about 2.5 miles below Shitike Creek

Deschutes River gains about 400 ft3/s from gro

water inflow (table 7). There is no significant gr

water inflow directly to the Deschutes River do

stream from this point. The total amount of gro

water discharging to the Deschutes and Crooke

0

100

200

300

400

500

600

165 155 145 135 125 

RIVER MILE

STRE

A

MFLOW, IN CUBIC FEET PER SECOND

5/11/92 Streamflow

5/16/94 Streamflow

Gage below Bend

Gage near Culver

Lower Bridge

Mouth of Squaw Creek

Cline Falls

Steelhead Falls

A

wbrey Falls

Figure 17. Gain in flow of the Deschutes River, Oregon, due to ground-water discharge between river miles 165 an

May 1992 and May 1994. (Some of the gain is due to ground-water discharge along the lower 2 miles of Squaw C
46

Rivers in the area extending from about 10 miles

above Lake Billy Chinook to Dry Creek is approximately 2,300 ft3/s. This is probably a conservative

estimate for the reasons previously discussed.

The ground-water discharge estimate in the

confluence area (2,300 ft3/s) cannot be simply added

to the discharge estimate for streams emanating from

the Cascade Range (2,600 ft3/s) to estimate average

net ground-water discharge to streams in the basin.

The resulting value exceeds the total estimated

ground-water recharge for the entire upper Deschutes

Basin. This is because the streams to which ground

water discharges in the upper basin lose some of

that water (as much as 600 ft3/s) back to the groundwater system through stream and canal leakage. This

water discharges once again in the confluence area.

Therefore, a fraction of the ground water discharged in

the confluence area has entered and been discharged

from the ground-water system twice.

Ground-water discharge in the confluence area

is controlled primarily by geology. Sceva (1960),

in a report prepared for the Oregon Water Resources

Board, was the first to describe the influence of the

geology on regional ground-water flow and discharge.

His basic conceptual model was largely corroborated

by subsequent data collection and analysis. In a later

report he states: “A barrier of rocks having a low

permeability transects the Deschutes River Basin near

Madras. This barrier forces all of the ground water to

be discharged into the river system... (Sceva, 19

p. 5).”

The Deschutes Basin is transected by a br

ridge composed of the John Day Formation, a r

unit of very low permeability that extends, with

varying degrees of exposure, from the Gray Bu

area north to the Mutton Mountains (outside an

northwest of the study area) and east into the Jo

Basin (fig. 4). This broad ridge is part of a regio

uplift extending from central to northeastern Or

known as the Blue Mountain anticline (Orr and 

1992). The John Day Formation in this area con

of tuffaceous claystone, air-fall and ash-flow tu

lava flows (Robinson and others, 1984). The rid

the John Day Formation represents an ancient u

that formed the northern and eastern boundary 

the basin into which the permeable Deschutes F

tion was deposited. North of Madras, the Desch

Formation, through which most regional ground 

in the upper basin moves, becomes increasingly 

and eventually ends. Because the John Day For

has such low permeability, ground water canno

move farther north in the subsurface and is forc

discharge to the Crooked and Deschutes Rivers

have fully incised the Deschutes Formation (fig

Analysis of stream-gaging data shows that there 

significant ground-water discharge to the Desch

River downstream from the area where the John 

Formation forms the walls of the river canyon.

Water table

5000

4000

3000

2000

1000

SEA

LEVEL

Deschutes River 

elevation profile 

Permeable rock

220 200 180 160

RIVER MILE

NOT TO SCALE

140 120 100 80

Ground-water flow

SW NE

Area of 

ground-water discharge

to the Deschutes River

Bend

Pelton Da

L

m

ower 

Bridge

Awbrey Falls

Cline Falls

Pringle Falls

Benham Falls

ELEVATION, IN FEET

Low permeability rock

?

? ?

Figure 18. Diagrammatic section showing the effect of geology on ground-water discharge along the Deschutes Riv

upstream of Pelton Dam.
47

Temporal Variations in Ground-Water Discharge to Streams

Ground-water discharge to streams not only

varies from place to place, but varies with time as well.

The rate of ground-water discharge varies on many

time scales, but for this study, annual and decadal time

scales are examined. Annual discharge variations are

driven by the seasonal variations in precipitation and

ground-water recharge. Decadal variations in groundwater discharge in the Deschutes Basin are driven by

variations in precipitation and recharge due to climate

cycles. Longer-term variations in discharge, occurring

over many decades, can be caused by long-term

climate trends. Ground-water discharge variations at

all of these time scales can be influenced by human

activity. Temporal variations in ground-water discharge

in the basin are discussed in the following paragraphs.

Virtually all the data on temporal variations in

ground-water discharge were derived from stream

gages, where continuous records of stream discharge

were recorded (fig. 11). Data from stream gages are

useful for estimating ground-water discharge only in

certain circumstances. Regulation of streamflow at

upstream dams or other control structures precludes

the use of some gages for estimating ground-water

discharge. If the gage is at a location where it is known

that the streamflow is virtually entirely from groundwater discharge, such as with spring-fed streams like

Fall River, then the gage provides a continuous direct

measurement of ground-water discharge. In such cases,

the gage can provide information on variations in

ground-water discharge at many time scales ranging

from daily to long term. In other circumstances, such

as along the lower Crooked River at Opal Springs,

streamflow can only be assumed to represent groundwater discharge during the driest months of the year

when surface runoff from upstream is negligible

compared to known inflow from springs. In cases such

as this, the gage cannot be used to evaluate seasonal

variations in ground-water discharge, but can provide information on year-to-year variations. In some

circumstances, a set of gages operated concurrently on

a stream can be used to estimate ground-water inflow

to the stream between the gages as long as there is

no unmeasured tributary inflow or diversion along the

intervening reach.

Stream-gage data suitable for estimating

temporal variations in ground-water discharge are

available for only a few locations in the upper

Deschutes Basin because stream gages are typically

located and operated for other reasons. However, the

main ground-water discharge settings are repre

in the available data.

Stream-gage data are available for a numb

of small spring-fed streams along the margin of 

Cascade Range in the southern part of the basin

including Cultus, Quinn, and Fall Rivers, and B

Creek. The flow in these streams is almost entir

ground-water discharge, as indicated by constan

flow throughout the year (fig. 14). The gages on 

streams provide an approximate continuous me

of ground-water discharge. The flow in these st

does vary seasonally, and they do exhibit annua

in flow. The magnitude of the peak flow is atten

and the timing of the peak flow is delayed when 

pared with runoff-dominated streams such as C

Deer, and Big Marsh Creeks (fig. 14). The diffe

between ground-water- and surface-water-domi

streams is apparent in the statistics of their mea

monthly flows (table 8). The range in mean mo

flows for surface-water-dominated streams is ov

200 percent of their mean annual flow. The mon

with the highest mean flows for surface-water-d

nated streams are May and June. The range in m

monthly flows for ground-water-dominated stre

contrast, is only 11 to 58 percent of their mean 

flows, and the high flow may occur any month f

May through September. The peaks in flow see

ground-water-dominated streams are caused by 

same snowmelt events that provide peak discha

to runoff-dominated streams. Because the water 

percolate through the soil and move through the 

surface before discharging to spring-fed stream

peaks in flow are attenuated and delayed.

The time lag between the annual peak sno

and the peak in the flow of these spring-fed stre

is proportional to the degree of attenuation of a

flow peak; in other words, the more subdued th

flow, the longer the time lag (Manga, 1996). A 

matical model for ground-water-dominated stre

in the Cascade Range developed by Manga (19

relates the degree of attenuation and the time la

the peak streamflow to the generalized geometr

hydraulic properties of the aquifers feeding the s

In Manga’s model, the annual recharge pulse ca

by snowmelt is essentially diffused along the len

the aquifer causing the attenuation and delay in 

peak flow. This suggests that streams fed by aqu

with large areas are likely to have more uniform 

and a longer delay between recharge events and 

flows when compared to streams fed by aquifer

small capture areas.
48

Table 8. Statistical summaries of selected nonregulated streams in the upper Deschutes Basin, Oregon

[Source: Moffatt and others, 1990; ft3/s, cubic feet per second]

Station name

Station

number

Period

of record

Mean

annual

flow

(ft3/s)

Highest

mean

monthly

flow

(ft3/s)

Month

of highest

mean

monthly flow

Lowest

mean

monthly

flow

(ft3/s)

Month

of lowest mean

monthly flow

Varia

perce

of m

annu

Deschutes River

below Snow Creek

14050000 1937–87 151 227 August 99 March 

Cultus River

above Cultus Creek

14050500 1923–87 63 75 July 50 February–March 

Cultus Creek

above Crane Prairie

Reservoir

14051000 1924–62 22 73 June 1.2 October 

Deer Creek

above Crane Prairie

Reservoir

14052000 1924–87 7.5 28 May 0.2 September 

Quinn River

near La Pine

14052500 1938–87 24 33 July 19 November–January 

Browns Creek

near La Pine

14054500 1923–87 38 43 September 34 February–March 

Fall River

near La Pine

14057500 1938–87 150 159 May 142 February 

Big Marsh Creek

at Hoey Ranch

14061000 1912–58 72 182 May 21 September 

Squaw Creek

near Sisters

14075000 1906–87 105 224 June 62 March 

Metolius River

near Grandview

14091500 1912–87 1,500 1,640 June 1,350 October 

The spring-fed streams in the southern Deschutes

Basin exhibit decadal flow variations in addition to

annual variations. Individual peak periods on Fall

River, for example, are roughly 5 to 14 years apart.

Decadal variations in annual mean discharge can be

substantial. Stream-gage data show that between 1939

and 1991 the annual mean flow of Fall River varied

from 81 to 202 ft3/s and the annual mean flow of

Cultus River ranged from 36 to 96 ft3/s. These decadal

variations in ground-water discharge are driven by

climate cycles. Comparing the ground-water discharge

variations with precipitation at Crater Lake in the

Cascade Range (both as cumulative departures from

normal) shows that periods of high ground-water

discharge generally correspond with periods of high

precipitation (fig. 19).

Stream-gage data also provide information on

temporal variations in ground-water discharge in

the Metolius River drainage. As mentioned in the

preceding section, the only long-term gage on the

Metolius River is in the lower part of the drainage

near Grandview, which measures discharge from a

relatively large area. Because the drainage area

represented by this gage includes runoff-domin

streams, the data cannot be used to evaluate sea

variations in ground-water discharge. Evaluatin

the late summer and early fall flows, when mos

streamflow is ground-water discharge, however

can provide information on the long-term variat

in ground-water discharge in the basin.

Before evaluating base flow to the Metoliu

River, the effects of tributary streams potentiall

carrying glacial meltwater during the late summ

must be considered. In figure 20, a graph of Oc

mean discharge values for the Metolius River is 

with similar graphs of Jefferson Creek and Whit

River. Subtracting the flow of Jefferson Creek a

Whitewater River shifts the graph of the Metoli

River downward, but does not affect the overall

shape of the graph or magnitude of variation (fi

This suggests that the variations in October mea

flows in the Metolius River are not greatly affec

these glacial streams and probably reflect variat

ground-water discharge.
49

0 

-100

100

200

300

400

1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1

YEAR

CUMULATIVE DEPARTURE FROM NORMAL PRECIPITATION, IN INCHES

AND ANNUAL MEAN FLOW, IN CUBIC FEET PER SECOND, OF ALL STREAMS 

EXCEPT THE METOLIUS RIVER 

Metolius River

Precipitation at Crater Lake

Cultus River

Quinn River

Fall River

Browns Ceek.

Cultus Creek

Deer Creek.

Figure 19. Cumulative departure from normal annual mean flows of selected streams in the upper Deschutes Basi

and cumulative departure from normal annual precipitation at Crater Lake, Oregon, 1947–91.

Metolius River at Grandview

0

200

400

600

800

1,000

1,200

1,400

1,600

1,800

1982 1984 1986 1988 1990 1992 1994 1996 1998

YEAR

OCTOBER MEAN FLOW, METOLIUS RIVER,

IN CUBIC FEET PER SECOND

Jefferson Creek

Whitewater River

Metolius River with Jefferson Creek and Whitewater River subtracted

20

40

60

80

100

120

140

160

180

0

Figure 20. October mean flows of the Metolius River (near Grandview), Jefferson Creek, and Whitewater River,

upper Deschutes Basin, Oregon, 1984–97.
50

Variations in long-term discharge of the Metolius

River at Grandview exhibit a pattern similar to that

seen in other Cascade Range streams. Comparison

of the annual mean discharge of the Metolius River

with precipitation at Crater Lake (both as cumulative

departures from normal) shows that variations in base

flow of the Metolius River follow variations in Cascade

Range precipitation to a large degree, as is the case

with other Cascade streams (fig. 19). Because of the

size of the drainage basin, the magnitude of the decadal

variation in ground-water discharge to the Metolius

River is less than that in the smaller ground-waterdominated streams in the upper basin. For example,

the 407 ft3/s variation in October mean discharge of the

Metolius River from 1962 to 1997 is about 30 percent

of the mean October discharge for the period. The

variation in October mean discharge for Fall River, by

comparison, is about 74 percent of the mean October

discharge flow for the same period.

Stream-gage data also allow evaluation of temporal variations in ground-water discharge in the area

near the confluence of the Deschutes and Crooked

Rivers. Data are available for reaches of both the

Crooked and Deschutes Rivers above Lake Billy

Chinook. In both cases, unmeasured tributary inflow

during parts of the year preclude analysis of seasonal

variations and allow analysis only of interannual and

longer-term variations.

Variations in ground-water discharge to the

Deschutes River in the confluence area can be evaluated by comparing discharge records from stream

gages below Bend and near Culver just above Lake

Billy Chinook. Seepage runs (table 5), discussed in a

preceding section, indicate that most of the groundwater discharge to this reach occurs within 10 miles

of Lake Billy Chinook.

Two major tributaries, Tumalo and Squaw

Creeks, join the Deschutes River between the Bend and

Culver gages. Neither of these tributaries have gaging

stations near their mouths. During the irrigation season

(April to November), most of the flow of these streams

is diverted. Tumalo Creek flows only a few cubic feet

per second at its confluence with the Deschutes River

during this time (table 5). Squaw Creek typically flows

about 100 ft3/s at its confluence with the Deschutes

River during the irrigation season (table 5), but nearly

all of this flow is from springs (including Alder

Springs) within 1.7 miles of the mouth. Flow in Squaw

Creek above the springs is typically only a few cubic

feet per second. It is reasonable, therefore, to consider

the net gain in streamflow along the Deschutes River

between the gages below Bend and near Culver 

the late summer and early fall to be almost entir

to ground-water discharge along the lower part 

reach, including the lower 2 miles of Squaw Cr

A graph of the difference between August 

flows at the Bend and Culver gages from 1953 

1997 (fig. 21) shows that August mean ground-

discharge varied from 420 to 522 ft3/s and exhi

a pattern of variation similar to other streams in 

basin. The 102 ft3/s variation in August mean g

water discharge to this reach of the Deschutes R

from 1962 to 1997 is about 22 percent of the m

August value. This is less than the base flow va

of 30 and 76 percent for the Metolius and Fall R

respectively, during this same period. The smal

variation in ground-water discharge to the Desc

River results from the larger size of the ground-

contributing area and the distance from the sour

recharge.

Variations in ground-water discharge to th

Crooked River can be evaluated using the gage 

Opal Springs. This gage is located in the midst 

most prominent ground-water discharge area in 

Deschutes Basin. A seepage run made in June 1

(table 5) showed that ground-water discharge b

Terrebonne and the gage at Opal Springs (a dist

of about 21 miles) exceeded 1,100 ft3/s, of whic

1,000 ft3/s entered the river in the lower 7 miles 

reach. During much of the year, the streamflow 

Opal Springs gage includes a large amount of s

runoff in addition to ground-water discharge (fi

During the irrigation season, however, most of 

flow above Terrebonne is diverted, and flow fro

stream into the ground-water discharge area is n

minuscule compared with the volume of ground

inflow. Therefore, the late-summer flow at the O

Springs gage is presumed to be almost entirely 

water discharge except during anomalous storm 

or reservoir releases.

August mean flows at the Opal Springs ga

between 1962 and 1997 (fig. 22), representing g

water discharge, exhibit climate-driven long-ter

variations apparent in other streams in the basin

mean discharge for the period from 1962 to 199

ranged from 1,133 to 1,593 ft3/s, a variation of

460 ft3/s, or 35 percent of the mean August disc

The variation in July mean flows for the same p

was only 28 percent. This variation is larger tha

would expect given the volume of discharge, ap

size of the ground-water contributing area, and 

observed variations in discharge to the Deschut
51

0

100

200

300

400

500

600

1950 1960 1970 1980 1990

YEAR

ESTIM

ATED 

AUGUST MEAN GROUND-W

ATER DISCHAR

GE,

 IN CUBIC FEET PER SECOND

Figure 21. Approximate August mean ground-water discharge to the middle Deschutes River between Bend and C

based on the difference between August mean streamflows at gages below Bend and near Culver, 1954–97.

(Fluctuations are caused by variations in ground-water discharge.)

0

500

1,000

1,500

2,000

2,500

3,000

3,500

4,000

4,500

5,000

1960 1965 1970 1975 1980 1985 1990 1995

YEAR

Monthly mean flows

August-mean flows

Figure 22. Monthly mean flows of the Crooked River at the gage below Opal Springs, 1962–97.

(The line connecting August mean flows approximates late-season ground-water discharge.)
52

This variation may be due to streamflow from above

the ground-water discharge area. The Crooked River

above the gage includes a very large area of runoffdominated streams and two major reservoirs. The

larger-than-expected variation may also be due to

variations in canal leakage, which contributes groundwater inflow to the lower Crooked River.

Variations in ground-water discharge to the

Metolius, Deschutes, and Crooked Rivers are driven

by the same climatic trends and parallel each other.

The variations, therefore, are additive and can

combine to account for variations in late season

monthly mean discharge on the order of 1,000 ft3/s

below the confluence area at the gage near Madras.

Late-season (July to September) mean monthly flows

at the gage near Madras, which are primarily groundwater discharge, average about 4,000 ft3/s. Therefore,

climate-driven variations in ground-water discharge

can account for late-season streamflow variations of

25 percent at Madras.

Analysis of stream-gage data from the lower

Crooked River from the early 1900s through the 1960s

shows an increase in ground-water discharge that is

attributed to irrigation canal leakage. The graph of

August mean discharge of the lower Crooked River

(fig. 23) includes data from two different gage sites.

Prior to the construction of Round Butte Dam a

filling of Lake Billy Chinook, the gage was ope

on the Crooked River at a now-inundated locati

near Culver, about 5.6 miles downstream from 

present gage location. The flow is different at th

two sites because the lower (former) site includ

flow from springs not measured by the present 

causing an offset between the two hydrographs

The hydrograph of August mean discharge of th

lower Crooked River shows an overall increase 

approximately 400 to 500 ft3/s between 1918 an

the early 1960s (fig. 23). The increase is given a

range because the exact amount is uncertain du

year-to-year variability in the flow. This steady, 

term trend of increasing discharge is not observ

other streams, such as the Metolius River, and d

not appear to be caused by climate. It is also dif

from later long-term variations in August mean 

This increase in base flow to the lower Crooked 

is, however, similar in volume to estimated ann

mean irrigation canal losses. Moreover, the grow

of the increase is similar to that of estimated ca

leakage (fig. 23). The return of water lost throu

canal leakage back to the surface as base flow t

Crooked River is consistent with ground-water 

directions in the area.

0

200

400

600

800

1,000

1,200

1,400

1,600

1,800

2,000

1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 

YEAR

ESTIMATED MEAN ANNUAL CANAL LEAKAGE AND

AUGUST MEAN FLOW, IN CUBIC FEET PER SECOND

Estimated annual mean canal leakage

Metolius River near Grandview flow

Crooked River near Culver flow

Crooked River below Opal Springs flow

Figure 23. August mean flows of the Crooked River below Opal Springs, the Metolius River near Grandview, and esti

annual mean leakage from irrigation canals, 1905–97.
53

Ground-Water Discharge to Wells

Ground water is pumped from wells for a variety

of uses in the upper Deschutes Basin, including

irrigation, public supply, and private domestic use.

Irrigation is primarily agricultural, but can include

watering of golf courses and parks. Public-supply

systems include publicly and privately owned water

utilities, which are typically located in urban and

suburban areas. Public-supply use includes not only

drinking water, but also commercial, industrial, and

municipal uses. Private domestic use generally refers

to pumpage by individual wells that typically supply a

single residence. Pumpage for each of these uses is

discussed in this section.

Irrigation Wells

Pumpage of ground water for irrigation was

estimated using water-rights information from the

State of Oregon and crop-water-requirement estimates

(fig. 24). Crop-water requirements were estimated, as

previously described, for each irrigated 40-acre tract in

the study area. The proportion of each tract irrigated

with ground water was identified using water-rights

information from the State of Oregon. A well serving

as the primary source of water was identified for each

tract irrigated using ground water. Where multiple

wells supply water to the same 40-acre tract, the

amount of water was proportioned between the wells

based on the instantaneous rate information in the

water-right files. For example, if it was determined

that the crop-water requirements plus irrigationefficiency requirements totaled 100 acre-ft/yr in a

particular 40-acre tract, and that there were two wells

with water rights listing instantaneous rates of 1 and

3 ft3/s, then the two wells would be assigned annual

pumpage rates of 25 and 75 acre-ft/yr respectively.

The crop-water requirements for all tracts, or

parts thereof, were summed for each well. These sums

were then divided by the irrigation efficiency (0.75)

to derive an estimate of the total pumpage from each

well. Water not lost through irrigation inefficiency

or transpiration by plants is assumed to return to the

ground-water system through deep percolation below

the root zone and not be consumptively used.

Pumpage of ground water for irrigation was

estimated to be about 14,800 acre-ft/yr (an average

annual rate of 20.4 ft3/s) during 1994, the year in

which the crop-water requirements were estimated.

Ground-water pumpage was estimated for each year

from 1978 through 1997 by adjusting the 1994

pumpage up or down using an index reflecting t

potential evapotranspiration and accounting for

the change in the number of water rights with ti

Potential evapotranspiration values were derive

from the DPM (described in a previous section 

this report) and adjusted to more accurately refl

rates measured by the BOR at the AgriMet site 

Madras. Estimated ground-water pumpage for

irrigation from 1978 to 1997 is shown in figure 

The geographic distribution of average annual g

water pumpage for irrigation from 1993 to 1995 

shown in figure 25.

Public-Supply Wells

Public water-supply systems use a large p

portion of the ground water pumped in the uppe

Deschutes Basin. Pumping for public water sup

has increased steadily in recent years in respons

population growth (fig. 26). Total ground-water 

age for public-supply use as of 1996 was estima

to be about 15,100 acre-ft/yr, an average rate of 

20.8 ft3/s. Public-supply pumpage is concentrat

primarily in urban and major resort areas, with 

tered pumpage by smaller, rural systems (fig. 27

Public-supply pumpage was estimated usi

data provided by operators of the 19 major mun

water systems and private water utilities in the u

basin. The quality and completeness of data fro

these systems varied widely. Some systems hav

izing flow meters on their wells, while others es

pumpage using hour meters and known or calcu

pumping rates. Complete records were not avai

for all systems for all years of interest. A variet

techniques was employed to estimate pumpage 

records were incomplete or missing. Where dat

early years were not available, pumpage was est

by using estimates of the number of individuals 

or the number of connections to the system. In 

where data were missing for certain time interv

pumpage was estimated by interpolating betwee

and later months or years. In some cases, total p

age for a system was available, but pumping rat

for individual wells within the system were onl

available for a few years or not at all. In such ca

the total pumpage each year was divided betwe

wells based on available data, and the proportion

constant from year to year.

Part of the ground water pumped for publ

supply returns to the ground-water system throu
54

0

2

4

6

8

10

12

14

16

18

20

1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 19

YEAR

ESTIMATED ANNUAL GROUND-WATER PUMPAGE FOR IRRIGATION, 

IN THOUSANDS OF ACRE-FEET PER YEAR

Figure 24. Estimated annual ground-water pumpage for irrigation in the upper Deschutes Basin, Oregon, 1978–

a variety of processes, such as seepage from sewage

infiltration ponds, leakage from transmission lines,

infiltration from on-site septic systems (drainfields),

and deep percolation during irrigation. The fraction

of public-supply pumpage not returned to the groundwater system through these processes is considered

to be consumptively used. The proportion of the gross

public-supply pumpage that is consumptively used

is not precisely known. Because most of the water

returned to sewage treatment plants is returned to the

ground-water system, subtracting the volume of water

delivered to these plants from the gross amount

pumped from wells can provide an estimate of the

amount of ground water that is consumptively used.

Measurements of ground-water pumpage and

wastewater flow for the cities of Redmond and Bend

provide information on the percentage of groundwater pumpage consumptively used. Monthly

measurements for Redmond from 1988 to 1997 show

that, depending on the month, 22 to 92 percent of

the ground water pumped is returned to the sewage

treatment plant as wastewater (Pat Dorning, City of

Redmond, written commun., 1999). Return flows for

the city of Bend are comparable to those of Redmond

(Roger Prowell, City of Bend, oral commun., 1999).

During winter, when water use is relatively low, 80 to

90 percent of the ground water pumped is retur

wastewater, and only 10 to 20 percent is unacco

for. During summer, when water production is a

four times the winter rate, only about 20 to 40 p

of the ground water pumped is returned as wast

water, leaving 60 to 80 percent unaccounted for

water not returned as wastewater is not, howeve

consumptively used. Part of the water not return

wastewater returns to the ground-water system

through leakage from supply and sewer lines. T

type of leakage may account for as much as 8 p

of the total pumpage (Jan Wick, Avion Water

Company, oral commun., 1999). A large amoun

the increased water production during the summ

is used for irrigation of lawns, gardens, and par

Much of this water is used consumptively, lost th

evaporation and transpiration by plants, but som

percolates below the root zone and returns to th

ground-water system. Because municipalities a

urban home owners generally employ relatively

efficient irrigation techniques such as sprinklers

as opposed to inefficient techniques such as floo

irrigation, it is probably reasonable to assume th

large proportion of the increased summer produ

is used consumptively, but the exact amount in

unknown.
56

0

2

4

6

8

10

12

14

16

18

20

1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 19

YEAR

ESTIMATED ANNUAL GROUND-WATER PUMPAGE FOR 

PUBLIC-SUPPLY USE, IN THOUSANDS OF ACRE-FEET PER YEAR

Figure 26. Estimated annual ground-water pumpage for public-supply use in the upper Deschutes Basin, Orego

1978–97. (Gross pumping figures do not represent actual consumptive use; a significant proportion of the pump

water returns to the ground-water system.)

Additional sources of error may be present in

consumptive-use estimates based on wastewater return

flow. In urban areas, some of the wastewater returned

to sewage treatment plants is lost through evaporation

from sewage lagoons or infiltration ponds. If sewage

effluent is used to irrigate fields, a considerable

amount may be lost through evapotranspiration.

Consumptive-use estimates may be low if it is

assumed that all the wastewater returned to sewage

treatment plants is returned to the ground-water

system.

Estimates of the proportion of ground-water

pumpage that is actually consumed and not returned

to the ground-water system are clearly influenced

by many sources of error and must be considered

approximate. Available data suggests that consumptive

use ranges from approximately 10 percent of the

total pumpage during winter, to approximately 50

to 70 percent during the high-water-use summer.

On an annual basis, about 43 percent of the ground

water pumped by the city of Redmond, for example,

is returned as wastewater, leaving 57 percent of

the water unaccounted for. Return-flow figures and

transmission-loss estimates suggest that consumptive

use of ground water in urban areas is probably somewhat less that 50 percent of the gross annual pumpage.

Private Domestic Wells

Not all residents of the upper Deschutes B

are connected to public water supplies; many re

private domestic wells. Private domestic well u

estimated using OWRD water-well-report files, 

from the Oregon Health Division, Drinking Wa

Section (Dennis Nelson, written commun., 199

population data from the State of Oregon (1999

1990 census data (U.S. Department of Commer

1993). As of 1995, an estimated 34,000 individ

about 27 percent of the population of the study 

obtained water from private domestic wells or s

water systems. The percentage of residents

on private wells varies between counties. As of 

about 22,000 people, or 24 percent of the popul

obtained water from private wells in Deschutes

County. In Jefferson County, about 1,900 peopl

12 percent of the population, relied on private w

In Crook County, about 8,000 people, 52 percen

the population, obtained water from private wel

An estimated 1,900 people relied on private we

Klamath County in the study area.

The amount of ground-water pumpage by

private domestic wells can be roughly estimated

based on number of individuals served by such 
58

Per capita water use in the upper Deschutes Basin,

estimated by using data from public water-supply

systems, varies considerably between systems.

Records from public water suppliers indicate that

average daily per capita water use for the largest

public-supply systems in the study area ranges from

100 to 300 gal/d. Some of these systems supply commercial and municipal uses, and the per capita figures

from them are not representative of rural dwellings.

Many of the private wells in the study area are in rural

residential areas served by irrigation districts, so well

water is not used for irrigation of lawns and gardens.

Because water from private domestic wells is used

primarily for indoor use and not irrigation, per capita

pumpage from rural residential domestic wells is considered for estimation purposes to be at the lower end

of the calculated range, 100 gal/d.

If an average per capita pumpage of 100 gal/d

is used, ground-water pumpage by private domestic

wells (assuming 34,000 individuals are served) is

approximately 3.4 million gal/d, which equals an

average annual rate of 5.3 ft3/s. As is discussed in the

previous section, all of this water is not used consumptively. Virtually all of the homes on private domestic

wells also use on-site septic systems, so most of the

water pumped is returned to the ground-water system

through drainfields. Actual consumptive use of ground

water by private domestic wells in the upper Deschutes Basin is, therefore, likely less than 1 to 2 ft3/s.

Ground-Water Discharge to Evapotranspiration

Most consumption of water by evapotranspiration occurs in the unsaturated zone. This water is

intercepted as it percolates downward through the

unsaturated zone prior to becoming ground water.

Evapotranspiration from the unsaturated zone is

accounted for by the DPM and occurs outside of the

ground-water budget. Thus, the evapotranspiration

of water from the unsaturated zone is not considered

ground-water discharge. There are, however, circumstances in which evapotranspiration does consume

ground water from the saturated zone. This occurs

when the water table is sufficiently shallow to be

within the rooting depth of plants, on the order of 5 to

10 ft deep. Evapotranspiration of water in this manner

is considered ground-water discharge.

Broad areas with shallow ground-water conditions as described above are rare in the upper

Deschutes Basin. The La Pine subbasin is the only

significant large region in the study area with shallow

ground-water conditions necessary for evapotra

tion from the water table. Areas of shallow grou

water occur in the drainages of the upper Metol

River and Indian Ford Creek as well, but these 

small in comparison to the La Pine subbasin. Th

potential amount of evapotranspiration from the 

table in the La Pine subbasin was estimated to ev

the significance of this process to the overall gr

water budget.

The DPM described earlier in this report c

culated the amount of potential evapotranspirat

throughout the study area. It also calculated the 

portion of the potential evapotranspiration satis

by evapotranspiration from the unsaturated zon

proportion of the potential evapotranspiration n

satisfied in this manner is the remaining amoun

could be satisfied by evapotranspiration from the 

table, and is termed the residual evapotranspira

The DPM estimated that the residual evapotran

tion in the La Pine area equals an average annu

instantaneous rate of about 5.7 × 10-8 ft/s (feet p

second) (22 in./yr), which is equivalent to abou

1.6 ft3/s/mi2. The probable area over which the 

table is within 10 ft of land surface in the La Pi

subbasin is estimated to be about 50 mi2, based 

water-level measurements in the La Pine subba

taken in June 1999. During that time of year, th

rate of evapotranspiration would be greatest. If 

maximum residual evapotranspiration is lost to 

transpiration over the entire 50 mi2, it would rep

an average annual rate of about 80 ft3/s. To tran

at the full residual evapotranspiration rate, how

the water table would have to be virtually at lan

surface. In reality, the water table is probably n

margin of the rooting depth of plants, so the act

amount of evapotranspirative loss from the wate

is probably much less than 80 ft3/s. The values 

evapotranspiration presented in this section are 

estimates, but serve to illustrate the magnitude 

probable ground-water discharge through evapo

piration for comparison with other parts of the g

water flow budget.

GROUND-WATER ELEVATIONS AND FLOW

DIRECTIONS

Hydrologists describe the force driving gr

water movement as hydraulic head, or simply, h

Ground water flows from areas of high head to 

of low head. In an unconfined aquifer, such as a 
59

deposit along a stream or a fractured lava flow near

land surface, the elevation of the water table represents

the head at the upper surface of the aquifer. Ground

water flows in the direction the water table slopes,

from high-elevation (high-head) areas toward lowelevation (low-head) areas. The change in head with

distance, or head gradient, is simply the slope of the

water table. Some aquifers, however, are confined by

overlying strata with low permeability called confining

units. A confined aquifer, for example, may be several

hundreds of feet below land surface. The water in

such an aquifer is often under pressure. When a well

penetrates the aquifer, the water will rise in the well

to some elevation above the top of the aquifer. The

elevation to which the water rises is the head at that

place in the aquifer. Water moves in confined aquifers

from areas of high head to areas of low head just as in

unconfined aquifers. Multiple confined aquifers can

occur one on top of another separated by confining

units. The heads in multiple confined aquifers may

differ with depth resulting in vertical head gradients.

If a well connects multiple aquifers with different

heads, water can flow up or down the well from the

aquifer with high head to the aquifer with low head.

The distribution of head in an unconfined aquifer is

represented by the elevation and slope of the water

table. The distribution of head in a confined aquifer

is represented by an imaginary surface known as a

potentiometric surface. A potentiometric surface can

be delineated by evaluating the static water-level

elevations in wells that penetrate a confined aquifer.

In this report, the distinction between confined

and unconfined aquifers is not critical to most of

the discussion and is generally not made. The term

ground-water elevation is used instead of head in the

following discussion because it is more intuitively

understandable. Furthermore, the term water table

is used loosely to describe the general distribution of

ground-water elevation in an area whether the aquifers

are confined or unconfined. The important concept

is that ground water moves from areas of high groundwater elevation (high head) to areas of low groundwater elevation (low head). In the upper Deschutes

Basin, ground-water elevations are highest in the

Cascade Range, the locus of ground-water recharge in

the basin, and lowest in the vicinity of the confluence

of the Deschutes, Crooked, and Metolius Rivers, the

principal discharge area.

The geographic distribution of ground-water

elevations in the upper Deschutes Basin was determined in this study using a variety of types of d

In the developed parts of the study area, primar

areas of privately owned land, water-level eleva

were determined by measuring water levels in w

In some instances, conditions precluded measur

and water levels reported by drillers were used. 

from geothermal exploration wells provided a s

amount of water-level information in the Casca

Range and at Newberry Volcano. Very few wate

wells exist in the vast tracts of public land that c

pose much of the upper Deschutes Basin. In tho

areas, the sparse water-well data was augmente

elevation data from large volume springs and ga

stream reaches. Major discharge features such a

represent points at which the water-table elevati

land-surface elevation coincide.

Horizontal Ground-Water Flow

In the upper Deschutes Basin, ground wat

moves along a variety of paths from the high-ele

recharge areas in the Cascade Range toward the

low-elevation discharge areas near the margins 

the Cascade Range and near the confluence of t

Deschutes, Crooked, and Metolius Rivers. The

generalized ground-water elevation map (fig. 28

based on hydraulic-head measurements in deep 

and on the mapped elevations of major springs 

gaining stream reaches, shows the general direc

of regional ground-water flow in different parts 

upper basin. The map is generalized and does n

reflect local areas of shallow ground water caus

irrigation and canal and stream leakage.

In the southern part of the upper Deschute

Basin, ground water flows from the Cascade Ra

(including the Mt. Bachelor area) towards the h

lakes area and the Deschutes and Little Deschu

Rivers in the La Pine subbasin. Ground water fl

from Newberry Volcano toward the La Pine sub

and toward the north. The water table in the La 

subbasin is relatively flat, with an elevation of a

4,200 ft and a slight gradient generally toward t

north-northeast. In this area the water table is sh

often within several feet of land surface. North 

Benham Falls, the gradient increases dramatica

the water table slopes steeply to the northeast. A

result, the regional water table, which is very cl

to land surface in the La Pine subbasin, is sever

hundred feet below land surface near Bend.
61

Ground-water elevations are relatively high

in the southeast part of the Deschutes Basin near

Millican, indicating that ground water flows from

that area toward the northwest into the lower parts

of the basin. As described previously, some water

likely enters the southeastern part of the Deschutes

Basin from the Fort Rock Basin (Miller, 1986). In

the northern part of the study area, ground water flows

from the Cascade Range to the northeast into the lower

part of the basin toward ground-water discharge areas

near the confluence of the Deschutes, Crooked, and

Metolius Rivers.

In the central part of the study area, around

Bend, Redmond, and Sisters, the water table is relatively flat between an elevation of 2,600 and 2,800 ft,

although there is a gradual gradient to the north toward

the confluence area (fig. 28). The water table in the

Bend area is generally hundreds of feet below land

surface. The northward slope of the water table is less

than the northward slope of the land, however, so the

water table is closer to land surface in the Redmond

area. North of Redmond, the deep canyons of the

Deschutes and Crooked Rivers are incised to the elevation of the regional water table, so ground water flows

toward, and discharges to, streams that act as drains to

the ground-water flow system. Water-level contours

are generally parallel to the canyons in the confluence

area, indicating flow directly toward the rivers.

A striking feature of the generalized water-table

map (fig. 28) is the linear zone of closely spaced

contours (indicating a high horizontal head gradient)

that trends northwest-southeast across the upper basin.

There are at least four possible explanations for this

feature. First, the feature generally follows the

topography. It also is likely related to the distribution

of precipitation, which shows a similarly oriented high

gradient region, particularly in the northern part of

the mapped area. The flattening of the water-table

surface to the northeast, which partly defines the highgradient zone, is likely due to permeability contrasts

related to the stratigraphy. The low-gradient area in the

northeastern part of the map corresponds to that part

of the Deschutes Formation where permeable fluvial

deposits are an important component. Lastly, the linear

zone could be, in part, an artifact of the geographic

and vertical distribution of head data, particularly

southeast of Bend where data are sparse. The

northwest-trending high-head-gradient zone does

not generally correspond with mapped faults.

Vertical Ground-Water Flow

Ground-water elevation (or head) can vary

vertically as well as horizontally. At many locat

wells with different depths have different water 

In recharge areas, where water enters the groun

water system, ground water generally moves do

ward and there is a downward head gradient (fig

In recharge areas, water-level elevations are low

in deep wells and higher in shallow wells. If a w

penetrates multiple aquifers in a recharge area, 

can flow downward in the well from one aquife

another. In areas where ground-water flow is pri

horizontal and there is little vertical movement 

water, vertical gradients are small. In discharge

areas, water from deep aquifers under pressure 

upward from depth and there is an upward head

gradient. In discharge areas, deep wells have hi

water-level elevations than shallow wells, and, i

upward head gradients are sufficiently large, wa

levels in deep wells can be above land surface, c

water from the wells to flow at land surface.

Downward head gradients are common th

out much of the upper Deschutes Basin, includi

Cascade Range and lower parts of the basin aro

Bend and Redmond. In the Cascade Range, the 

amount of recharge causes downward movemen

ground water and strong downward head gradie

Evidence of this downward flow in the Cascade 

is commonly seen in temperature-depth logs of

geothermal wells (Blackwell, 1992; Ingebritsen 

others, 1992). Temperature data show downwar

to a depth of at least 1,640 ft below land surface 

exploration well drilled near Santiam Pass (Blac

1992). Similar large downward head gradients w

observed in the Mt. Hood area in the Cascade R

north of the study area by Robison and others (

Downward head gradients in the lower pa

the basin result primarily from artificial recharg

leaking irrigation canals. Ground-water elevatio

are artificially high in areas around networks of 

ing irrigation canals. In some places, artificially 

ground-water levels are observed only in scatte

wells close to major canals. In other places, suc

north and northwest of Bend, high ground-wate

elevations are maintained over a broad region by 

leakage. There are also isolated areas of shallow

ground water that may be related to natural rech

from stream leakage.
62

8,000

7,000

6,000

5,000

4,000

3,000

2,000

1,000

SEA

LEVEL

Less than 4 inches per year recharge

22-137 inches

per year Three recharge Sisters

area

Low permeability rock

NOT TO SCALE

Water table

Land surface

Flow direction

Line of equal head

Area of high recharge ­

large downward flow component

SW NE

Area of low recharge ­

small downward flow component

Discharge area ­

upward flow component

Sisters area

Deschutes River

Crooked River

Juniper Butte

ELEVATION, IN FEET

4-22 inches

per year

recharge

Figure 29. Diagrammatic section southwest-northeast across the upper Deschutes Basin, Oregon, showing flow direct

and lines of equal hydraulic head.

Separate sets of water-level elevation contours

for shallow wells (generally 100 to 300 ft deep) and

deep wells (generally 500 to 900 ft deep) were drafted

for the area around Bend, Redmond, and Sisters

(fig. 30). In the area north and northwest of Bend,

water-level elevations in shallow wells are 200 to

400 ft higher than water-level elevations in deep wells.

At some locations, water levels in shallow and deep

wells differ by over 500 ft. The shape and location

of this area of high water levels suggests that it is

caused by canal losses; for the most part it does not

coincide with potential natural sources of recharge.

Caldwell (1998) showed that shallow ground water

is isotopically very similar to canal and stream water,

which also suggests that canal and stream leakage

are a principal source of recharge for shallow ground

water.

There are isolated areas in the upper Deschutes

Basin where anomalously high ground-water elevations likely result from natural causes. Such areas

are present along the Deschutes River about halfway

between Bend and Redmond (near Awbrey Falls)

and west of Redmond. Elevated shallow water levels

in these areas are likely caused by natural leakage

from the Deschutes River. The relatively high shallow ground water in the Sisters area is also probably

natural, as no significant source of artificial rech

is present.

Local recharge from leaking irrigation can

throughout the populated areas in the lower bas

and the resulting vertical head gradients, cause 

level elevations to vary from well to well in an 

depending on the depth. In addition, water-leve

elevations can vary as the canals are turned on a

off. Consequently, it can be difficult to accurate

dict the depth to water at many locations, partic

where data from wells are sparse.

Upward head gradients are not commonly

encountered in the upper Deschutes Basin. The

are a number of possible causes for this. There 

widespread artificial recharge from canal leakag

and deep percolation of irrigation water through

much of the populated area resulting in widespr

downward gradients over most of the area wher

there are data. In addition, the streams to which 

ground water discharges in the lower basin have 

deep into the aquifer system, allowing much of 

water to discharge laterally without upward ver

movement. Finally, there are few wells that pen

to depths below the elevation of streams in the m

discharge area, where upward gradients would 

expected.
63

8 9 10 11 12 13

19

18

17

16

15

13

44o00'

44o30'

121o45' 30' 121o15'

Sisters

Redmond

Bend

Lower

Bridge

Cline

Falls

Terrebonne

97

97

20

20

126

126

Sparks

Lake

Suttle

Lake

Hosmer

Lake

Bridge

Cr

Indian

Ford

River

Squaw

Creek

Creek

Creek

Tumalo

DESCHUTES

Awbrey RIVER

Falls

Benham

Falls

Steelhead

Falls

0 5 10 MILES

0 5 10 KILOMETERS

Arnold

Canal

Tumalo Feed Canal

Central Oregon

Canal

North Unit

Main Canal

Squaw Creek

Canal

Black

Butte

Middle

Sister

North

Sister

South

Sister

Broken

Top

Lava

Island

Trail

Crossing

Cline

Buttes

Mt

Bachelor 5000

5000

4200

3200

3800

3600

3400

3000

2800

4000

5200

5600

5200

5400

4800

4400

4600

2600

EXPLANATION 

Line of equal hydraulic head — In deep zones

Line of equal hydraulic head — In shallow zones

Field-located well

5000

3000

3000

3400

3200

3000

2800

2800

2800

2600

2600

Figure 30. Generalized lines of equal hydraulic head for shallow and deep water-bearing zones in the central part of the 

upper Deschutes Basin, Oregon. (Elevated heads in shallow zones are due to infiltration of water from leaking irrigation 

canals, on-farm losses, and stream leakage.) 

A substantial upward head gradient exists in 

the area of the lower Crooked River at depths below 

river level. A 740-ft well drilled near river level at 

Opal Springs had an artesian flow of 4,500 gal/min 

and a shut-in pressure of 50 pounds per square inch, 

indicating that the aquifer tapped by the well has a 

hydraulic head (water-level elevation) over 115 ft 

above the elevation of the river. This large upward 

gradient indicates upward ground-water flow toward 

the river.
64

FLUCTUATIONS IN GROUND-WATER LEVELS

The elevation of the water table is not static; it

fluctuates with time in response to a number of factors,

the most important of which are variations in recharge,

canal operation, and pumping. In this section, groundwater-level fluctuations in the upper Deschutes Basin

are described, the controlling factors identified, and

the implications with regard to the regional hydrology

are discussed.

Ground-water-level fluctuation data are collected

by taking multiple water-level measurements in the

same well over a period of time. Multiple water-level

measurements are available for 103 wells in the upper

Deschutes Basin. These wells were monitored for

periods ranging from less than 1 year to more than

50 years; measurements were taken at intervals ranging from once every 2 hours (using automated recording devices) to once or twice a year. Fourteen wells in

the basin have been monitored by OWRD for periods

ranging from 9 to more than 50 years. Generally,

measurements have been taken in these wells one to

four times a year. Seventy-three wells were measured

quarterly during this study for periods ranging from

1 to 4 years. Nineteen of these wells also were measured quarterly for 1 to 2 years during the late 1970s.

Sixteen wells were instrumented with continuous

recorders, devices that measured and recorded the

water-level elevation every 2 hours. These shortinterval measurements effectively create a continuous

record of water-level elevation changes. Graphs 

water-level fluctuations in all of these wells are 

lished in the data report for this study (Caldwel

Truini, 1997).

Large-Scale Water-Table Fluctuations

The most substantial ground-water-level

fluctuations in the upper Deschutes Basin, in te

both magnitude and geographic extent, occur in 

adjacent to the Cascade Range, including parts 

La Pine subbasin. These fluctuations are exemp

by the hydrographs of wells 21S/11E-19CCC, n

La Pine, and 15S/10E-08ACD, near Sisters (fig

The water level in both these wells fluctuates up 

20 ft with a cycle averaging roughly 11 years. A

comparison of these water-level fluctuations wi

precipitation at Crater Lake in the Cascade Ran

(fig. 31) indicates that periods of high ground-w

level elevations generally correspond to periods 

high precipitation, and low water-level elevation

respond to periods of low precipitation. This re

of course, is to be expected. During periods of h

precipitation, the rate of ground-water recharge

exceeds, at least temporarily, the rate of dischar

When ground-water recharge exceeds discharge

the amount of ground water in storage must inc

causing the water table to rise. During dry perio

contrast, the rate of discharge may exceed the r

of recharge, and ground-water levels drop as a r

-20

0

20

40

60

80

100

120

140

1960 1965 1970 1975 1980 1985 1990 1995 2000

YEAR

DEPTH TO WATER, IN FEET

Well 21S/11E-19CCC

Well 15S/10E-08ACD

Crater Lake Precipitation - Cumulative departure from normal

20

0

-20

-40

-60

-80

-100

-120

-140

Figure 31. Static water levels in two long-term observation wells in the upper Deschutes Basin, Oregon, and cumu

departure from normal annual precipitation at Crater Lake, Oregon, 1962–98.
65

Fluctuations in the water-table elevation in

response to variations in recharge are most prominent

in the Cascade Range, the primary recharge area.

A comparison of hydrographs of wells at varying

distances from the Cascade Range (fig. 32) shows

that as distance from the recharge area increases, the

magnitude of fluctuations decreases, and the timing of

the response is delayed.

During the period from 1993 through early 1999,

ground-water levels in and near the Cascade Range,

such as in wells 14S/9E-08ABA and 15S/10E-08ACD,

rose over 20 ft in response to an abrupt change from

drought conditions to wetter-than-normal conditions.

Wells 15S/10E-36AAD2 and 15S/10E-02CDA, a

few miles to the east of Sisters, farther away from the

Cascade Range, showed a smaller rise in water level

(less than 20 ft), and a slight delay in response. Well

14S/12E-09ACB several miles farther east near Lower

Bridge, exhibited only a slight rise in water level,

less than 2 ft, in response to the end of the drought,

and an apparent delay in response. Long-term trends

in wells with seasonal fluctuations, such as well

14S/12E-09ACB, are evaluated by comparing annual

high and low water levels from year to year. Farther

east near Redmond, water levels in wells 15S/13E04CAB and 15S/13E-18ADD had barely stopped

declining even 2 years after the end of the drought.

Water levels in these wells had not started to rise as

of early 1999.

Long-term records show that the water level in

well 15S/13E-18ADD has fluctuated about 10 ft since

1971 compared to 23 ft in well 15S/10E-08ACD to the

west closer to the recharge area (Caldwell and Truini,

1997, fig. 8). In addition, the decadal-scale peaks and

troughs in the hydrograph of well 15S/13E-18ADD

are broad and lag those of the well 15S/10E-08ACD

by roughly 2 years.

The eastward-increasing delay in the waterlevel response to changes in recharge in the Cascade

Range is depicted by a series of maps in figure 33.

These maps show the annual direction of water-level

change from March 1994 to March 1998 for observation wells throughout the upper basin. From March

1994 to March 1995, during the drought, water levels

dropped in nearly all wells. Between March 1995 and

March 1996, water levels in wells along the Cascade

Range margin rose while water levels in wells to the

east continued to decline. Over the next 2 years, the

trend of rising water levels migrated eastward.

The attenuation and delay of water-level

fluctuations with distance from the recharge sou

is analogous to the attenuation and delay in gro

water discharge peaks with increasing basin siz

as discussed in the previous section. The effects 

recharge variations are diffused with distance in 

aquifer system.

Water-level fluctuations are attenuated wi

increasing depth as well as with increasing hori

distance from the recharge area. This can be see

comparing the hydrographs of wells 21S/11E-1

and 22S/10E-14CCA, which are about 5 miles a

geographically similar settings in the La Pine su

(fig. 34). Well 21S/11E-19CCC is 100 ft deep a

duces water from a sand and gravel deposit betw

depth of 95 and 100 ft. Well 22S/10E-14CCA is 

deep and taps water-bearing zones between 485 

545 ft below land surface within a thick sequen

of fine-grained sediment. The water level in the 

21S/11E-19CCC was declining until early 1995 

it started to rise in response to the end of droug

conditions. The water level rose over 15 ft by e

1997 in a manner similar to wells close to the C

Range. The water level in well 22S/10E-14CCA

contrast, declined until early 1996, and by 1999 

risen only about 7 ft in response to the end of d

conditions.

Local-Scale Water-Table Fluctuations

In addition to basinwide ground-water-ele

fluctuations, smaller-scale, localized water-tabl

fluctuations occur. These more isolated water-ta

fluctuations are caused by varying rates of rech

from local sources, such as leaking streams and 

and by ground-water pumping.

Water-level fluctuations due to irrigation c

leakage occur in many wells throughout the irri

areas in the central part of the study area, with w

levels rising during the irrigation season when c

are flowing and dropping when canals are dry. T

magnitude of these annual fluctuations varies w

proximity of the well to the canal, the depth of 

well, and the local geology. Annual fluctuations 

canal leakage of nearly 100 ft have been docum

(see well 17S/12E-08ABD in Caldwell and Tru

(1997), p. 20), although fluctuations in the rang

1 to 10 ft are more common.
66

95

105

115

125

15S/10E-36AAD2

15S/13E-04CA

280

290

300

310

140

150

160

280

290

300

310

160

170

180

14S/12E-09ACB

220

230

240

270

280

290

DEPTH TO WATER, IN FEET

DATE

1993 1994 1995 1996 1997 1998 1999

Figure 32. Variations in static water levels of selected wells at various distances from the Cascade Range, 1994–98. (The

hydrographs show that the abrupt rise in water level in response to the change from drought conditions to wetter-than-normal

conditions observed in the Cascade Range [uppermost hydrograph] is attenuated and delayed eastward out into the basin.)
68

0

10

20

30

40

50

60

DATE

1993 1994 1995 1996 1997 1998 1999

DEPTH TO WATER, IN FEET

Well 21S/11E-19CCC (100 ft deep)

Well 22S/10E-14CCA (550 ft deep)

Figure 34. Static water-level variations in a shallow well and a deep well in the La Pine subbasin, Oregon.

Ground-water levels can respond rapidly to canal

leakage, even at considerable depths, particularly in

areas where fractured lava dominates in the subsurface.

The water level in well 18S/12E-03DDC responds in

a matter of days to the operation of main irrigationdiversion canals, which are about one-half mile away

(fig. 35). The water level in this well starts to rise

shortly after the canals start flowing and starts to drop

soon after they are shut off for the season, peaking

late in the irrigation season. In addition, the water table

responds to periods of short-term operation of the

canal, typically for several days during the winter for

stock watering. The static water level in well 18S/12E03DDC is over 600 ft below land surface, and the

shallowest wells in the area have water levels of 300

to 400 ft below land surface. The rapid response of the

water table to canal leakage at such depth is likely

due to rapid downward movement of water through

interconnected vertical fractures in the lava flows.

Water-table fluctuations can be more subdued and

delayed in areas underlain by sedimentary materials

where there are no vertical fractures and there is more

resistance to downward movement of water. Well

15S/13E-04CAB (fig. 36) shows an annual waterlevel fluctuation that differs substantially from that

of well 18S/12E-03DDC (fig. 35). The amount of

fluctuation is somewhat less and the hydrograph is

smooth, nearly sinusoidal, reflecting no short-term

effects due to winter stock runs. In addition, the annual

peak water level in well 15S/13E-04CAB, which

occurs in October or November, is much later than that

of well 18S/12E-03DDC, which occurs in Augu

September. The hydrograph of well 15S/13E-04

in figure 36 also shows a year-to-year decline in

water levels due to drought effects superimpose

the annual fluctuations.

Water levels are affected by variations in 

flow as well as canal operation. In areas where 

elevations are above the adjacent ground-water 

tions, streams typically lose water to the ground

system due to leakage through the streambed. I

areas, the rate of stream leakage is not constant

varies with streamflow. As streamflow increase

the elevation of the stream rises, a larger area o

stream bed is wetted providing a larger area thr

which water can leak.

The most substantial stream losses measu

the basin occur along the Deschutes River betw

Sunriver and Bend, where the river loses, on av

about 113 ft3/s (fig. 12). The amount of loss is k

to be stage-dependent and to vary with streamfl

(fig. 13). This means that the ground-water rech

in the vicinity of the Deschutes River between B

Falls and Bend varies with streamflow as well.

The variations in local recharge caused by 

in streamflow cause water-level fluctuations in 

wells between Benham Falls and Bend (fig. 37)

stage and discharge in the Deschutes River in th

is controlled by reservoir operations upstream. 

flow is highest from April to October as water i

leased from the reservoirs to canal diversions ne
69

0

20

40

60

80

100

120

140

CANAL FLOW RATE, IN CUBIC FEET PER SECOND 160

180

200

6

6

6

6

6

6

6

6

6

6

6

Flow rate, Arnold Canal

Depth to water, Well 18S/12E-03DDC

DATE

1994 1995 1996 1997

Figure 35. Relation between static water-level variations in a deep well near Bend, Oregon, and flow rate in a nea

irrigation canal. CANAL FLOW RATE, IN CUBIC FEET PER SECOND

0

100

200

300

400

500

600

700

Flow Rate, Pilot Butte Canal

 Depth to Water, Well 15S/13E-04CAB

2

2

2

2

2

2

2

2

DATE

1994 1995 1996 1997 1998 1999

Figure 36. Relation between static water-level variations in a well near Redmond, Oregon, and flow rate in a near

irrigation canal.

As a result, changes in streamflow (and stage) can

be relatively abrupt. The water level in well 19S/11E16ACC, about 500 ft from the river near the Benham

Falls gage, rises and falls in response to river stage

(fig. 37). Abrupt changes in streamflow usually

manifest in the well within a few to several days.

These effects are much less pronounced, however,

in wells farther from the river. The water level in

well 18S/11E-21CDD, about 1 mile from the river,

also fluctuates in response to river stage, but the

fluctuations are subdued and the hydrograph is nearly

sinusoidal, showing only the slightest inflections

in response to abrupt changes in streamflow. In

addition, the peaks and troughs in the hydrograph

of well 18S/11E-21CDD lag those of well 19S/

16ACC and river stage by 1 to 2 months.

The relation between ground-water levels 

streamflow is apparent in ground-water discharg

as well as in recharge areas; however, the proce

reversed. In areas of losing streams (recharge ar

streamflow variations can cause water-table fluc

tions as described in the previous paragraph. In 

water discharge areas, however, water-table fluc

tions cause variations in streamflow. This is illu

by comparing a graph of the discharge of Fall R

a spring-fed stream, with a graph of typical lon

term water-table fluctuations at the Cascade Ra

margin as seen in well 15S/10E-08ACD (fig. 38
70

WATER-LEVEL ELEVATION FOR DESCHUTES RIVER

AND WELL 19S/11E-16ACC, IN FEET

DATE

1994 1995 1996

4,125

4,130

4,135

4,140

4,145

4,150

River Stage

Well 19S/11E-16ACC, 500 ft from river

Well 18S/11E-21CDD, 5,000 ft from river

3

3

3

3

3

3

Figure 37. Relation between static water-level variations in two wells at different distances from the Deschutes Rive

stage of the river at Benham Falls.

0

50

100

150

200

250

1960 1965 1970 1975 1980 1985 1990 1995

YEAR

MONTHLY MEAN DISCHAR

GE FOR FALL RIVER,

IN CUBIC FEET PER SECOND

Fall River

Well 15S/10E-08ACD

12

10

11

13

90

80

Figure 38. Relation between monthly mean discharge of Fall River and static water-level variation in a well near Sis

Oregon, 1962–97.

It can be seen that spring flow increases during

periods when the water table is high, and decreases

when the water table is low. This process works on

a larger scale to cause the temporal variations in

ground-water discharge to major streams described

previously.

Water-table fluctuations can be caused by

ground-water pumping as well as by variations in

recharge. When a well is pumped, the water table in

the vicinity of the well is lowered due to the removal

of ground water from storage. A conical depression

centered around the well develops on the water table

(or potentiometric surface in the case of a confined

aquifer) and expands until it captures sufficient discharge and/or induces enough new recharge to 

the pumping rate. After pumping ceases, the wa

table recovers as the aquifer returns to pre-pum

conditions. Key factors that determine the magn

of water-table fluctuations caused by pumping a

the aquifer characteristics, the rate and duration 

pumping, the presence of aquifer boundaries, an

the number of wells. In aquifers that have low p

ability, pumping-induced water-table fluctuation

be large and even interfere with the operation of 

wells. If the long-term average pumping rate ex

the rate at which the aquifer can supply water, w

levels will not recover fully and long-term water

declines will occur.
71

Water-table fluctuations caused by groundwater pumping are apparent in only a few of the

wells monitored in the upper Deschutes Basin.

Pumping effects appear to be small (less than a

few feet of drawdown), seasonal in nature, and of

limited geographic extent. No long-term water-level

declines caused by pumping are apparent in any of

the data.

Nearly all of the wells that were measured

quarterly and that show annual fluctuations have

high water levels during or shortly after the irrigation

season, indicating that the water-table fluctuation

is caused by canal leakage. A few of the wells that

were measured quarterly show low water levels during

the summer, suggesting a possible influence from

irrigation pumping, but the small number of waterlevel measurements prevents any definite conclusions.

These occurrences are not widespread.

Of the 16 wells that had continuous water-level

recorders, pumping effects are apparent only in well

14S/12E-09ACB in the Lower Bridge area (fig. 39).

This unused well shows an annual cycle in which the

water level drops during the irrigation season, from

about April to about September, and then rises during

the off season. The annual variation is approximately

2 to 3 ft. The shape of the hydrograph of this well

indicates drawdown and recovery most likely due

to pumping of an irrigation well about a mile away.

Although irrigation pumping causes a seasonal waterlevel decline in this well, there is no evidence of any

long-term water-level decline. The only obvious

long-term water-level trend seen in the well is the

basinwide trend related to climate cycles. The lack

of any apparent long-term pumping effects in this well

is significant, because the Lower Bridge area contains

the highest concentration of irrigation wells in the

basin.

Water levels in the two other centers of groundwater pumping in the basin, the Bend and Redmond

areas, show no apparent influence from ground-water

pumping. Large amounts of ground water are pumped

in both of these areas for public water-supply use,

yet no pumping-related seasonal or long-term trends

are apparent in observation well data. Any pumping

influence is likely small due to the high aquifer

permeability, and is undetectable due to the masking

effects of canal leakage and climate-driven water-level

fluctuations.

Ground-water levels in part of Jefferson C

rose dramatically in response to the filling of La

Billy Chinook behind Round Butte Dam in 196

Water levels in two wells (11S/12E-21ABB and

11S/12E-26AAC) monitored by Portland Gener

Electric, on opposite sides of the dam and abou

mile away, rose approximately 120 and 100 ft,

respectively, within about 10 years of filling of 

reservoir (fig.40). Because these are the only tw

wells monitored in the area with records extend

back to the time prior to the filling of the reserv

the full extent and magnitude of the effects of th

reservoir are not clearly known. A comparison 

water-level elevations mapped by Stearns (1931

with those mapped during this study (fig. 28) su

that water levels have risen as much as 100 ft ov

fairly large region from Round Butte, south to J

Butte, and extending east as far as Highway 97

Increases in water-level elevation were likely ev

greater close to the reservoir. No data are availa

evaluate the probable water-level rise west and 

of the reservoir, but water levels were almost ce

similarly affected. Water levels appear to have r

north of Round Butte in the vicinity of Lake Sim

as well, but data are sparse and the magnitude a

extent of any water-level rise are unknown. Alth

data are scarce, water levels appear not to have 

affected as far north and east as Madras. A 1953 

level measurement in one of the city of Madras 

supply wells is comparable to measurements m

recently, long after the effects of Lake Billy Ch

should have been apparent.

Some of the wells in Jefferson County sho

anomalous rising water-level trend that appears 

have started in the mid-1980s. The hydrograph 

11S/12E-26AAC (fig. 40) shows that the water 

appeared to have largely stabilized in response 

filling of Lake Billy Chinook by the mid 1970s

then started an upward trend beginning about 1

rising over 20 ft since that time. Of the four oth

wells in the vicinity with sufficient record, two 

not show this recent rising trend (fig. 40, well

11S/12E-21ABB), and two show water level ris

approximately 2 and 6 ft. This local water-table 

an enigma in that it occurs during a period when 

levels were dropping throughout much of the up

basin as a result of drought. There are no appar

changes in irrigation practices or canal operatio
72

167

168

169

170

171

172

DATE

1994 1995 1996 1997 1998 1999

DEPTH TO WATER, IN FEET

Figure 39. Static water level in an unused irrigation well near Lower Bridge (14S/12E-09ACB), showing seasonal pumping

effects from nearby irrigation wells and long-term climatic effects. DEPTH TO WATER FOR 11S/12E-21ABB, IN FEET

DEPTH TO WATER FOR 11S/12E-26ACC, IN FEET

250

300

350

400

450

500

1960 1965 1970 1975 1980 1985 1990 1995

DATE

Well 11S/12E-21ABB

Well 11S/12E-26AAC

650

700

750

800

850

900

Figure 40. Water levels in two wells near Round Butte Dam, showing the rise in ground-water elevations caused by

the filling of Lake Billy Chinook.

that could account for the observed upward trend.

Water levels in wells in the Madras area rose after the

city changed their primary source of water from wells

to Opal Springs and greatly reduced their groundwater pumping, but this occurred in 1987, 2 years

after the water level appears to have started to rise in

well 11S/12E-26AAC (fig. 40). Although not entirely

coincident, this reduction in pumping may have

contributed to the observed water-level rise. It is also

possible that the rise is a boundary effect related to

the filling of Lake Billy Chinook, implying that the

ground-water system is not yet in equilibrium with the

reservoir even though water levels appeared to have

stabilized in the late 1970s.
73

SUMMARY AND CONCLUSIONS

Regional ground-water flow in the upper Deschutes Basin is primarily controlled by the distribution

of recharge, the geology, and the location and elevation of streams. Ground water flows from the principal

recharge areas in the Cascade Range and Newberry

Volcano, toward discharge areas along the margin

of the Cascade Range and near the confluence of the

Deschutes, Crooked, and Metolius Rivers.

At the regional scale, distribution of recharge

mimics that of precipitation. The annual precipitation

rate shows considerable geographic variation throughout the upper Deschutes Basin. The Cascade Range,

which constitutes the western boundary of the basin,

locally receives in excess of 200 inches per year,

mostly as snow. The central part of the study area,

in contrast, typically receives less than 10 inches per

year. The young Quaternary volcanic deposits and thin

soils in the Cascade Range allow rapid infiltration of

much of the rain and snowmelt, making the Cascade

Range the locus of ground-water recharge for the

basin. The average annual rate of recharge from

precipitation basinwide (1962–97) is about 3,800 ft3/s

(cubic feet per second). Precipitation provides relatively little ground-water recharge in the low-elevation

areas in the central part of the basin; however, leaking

irrigation canals are locally a significant source of

recharge. It is estimated that 46 percent of the water

diverted for irrigation is lost through canal leakage.

The average annual rate of leakage from irrigation

canals during 1994 was estimated to be 490 ft3/s. Part

of the ground water recharged in the Cascade Range

discharges to spring-fed streams at lower elevations

in the range and along margins of adjacent lowlands.

The remainder of the ground water continues in the

subsurface toward the central part of the basin, where

most of it discharges to the Deschutes, Crooked, and

Metolius Rivers in the vicinity of their confluence.

Most ground water in the upper Deschutes Basin

flows through Neogene and younger deposits of

the Cascade Range and Deschutes Formation. The

underlying late Eocene to early Miocene deposits

of the John Day Formation and the hydrothermally

altered rocks at depth beneath the Cascade Range

generally have very low permeability and are neither

a significant source of ground water nor a medium

through which it can easily flow. These older rocks

crop out along the northern and eastern margins of the

study area and underlie much of the upper basin at

depth. Low-permeability rock units constitute the

lower, northern, and eastern boundaries to the re

flow system.

The interaction between ground water and

streams is controlled largely by the relative elev

of the water table and adjacent streams. In the L

subbasin, south of Benham Falls, the water-tabl

elevation is near land surface. Stream gains and 

along most of the Deschutes and Little Deschut

Rivers in this area are small, indicating relativel

net exchange between ground water and surface 

North of Benham Falls, the northward slope of 

water table is larger than the slope of the land s

so depths to ground water increase northward to

Bend. In the central and eastern parts of the stud

ground-water elevations are typically hundreds 

below the elevations of streams. Although grou

water levels are considerably below stream elev

in this area, streams do not lose appreciable am

of water, because streambeds have been largely 

by infiltration of fine sediment. One notable exc

is the Deschutes River, which loses on average

approximately 113 ft3/s between Sunriver and B

likely into the youthful Holocene basalt erupted 

Lava Butte.

The Deschutes and Crooked Rivers have i

canyons in the northern part of the study area. T

canyons become increasingly deep northward to

Lake Billy Chinook, reaching depths of several

hundred feet below the surrounding terrain. Ab

to 15 miles above their confluence, the canyons 

Deschutes and Crooked Rivers are of sufficient 

to intersect the regional water table, and both st

gain flow from ground-water discharge. Seepag

show that the Deschutes River and lower Squaw 

combined gain about 400 ft3/s from ground-wa

discharge in this area prior to entering Lake Bil

Chinook, and the lower Crooked River gains ab

1,100 ft3/s before entering the lake. Ground-wa

discharge to Lake Billy Chinook is roughly 420 

The total ground-water discharge in the conflue

area is approximately 2,300 ft3/s. This ground-w

discharge, along with the flow of the Metolius R

(which is predominantly ground-water discharg

during the dry seasons), makes up virtually all th

of the Deschutes River at Madras during the sum

and early fall.

Geologic factors are the primary cause of 

large ground-water discharge in the confluence 

The permeable Neogene deposits, through whic

virtually all regional ground water flows, becom
74

increasingly thin northward as the low-permeability

John Day Formation nears the surface. The John Day

Formation is exposed in the canyon of the Deschutes

River about 10 miles north of Lake Billy Chinook near

Pelton Dam, marking the northern extent of the permeable regional aquifer system. Most of the regional

ground water in the upper basin discharges to the

Deschutes and Crooked Rivers south of this location.

There is no appreciable ground-water discharge

directly to the Deschutes River downstream of this

point, and the small gains in streamflow that do occur

result primarily from tributary inflow.

Geological evidence and hydrologic budget

calculations indicate that virtually all ground water

not consumptively used in the upper Deschutes Basin

discharges to the stream system upstream of the

vicinity of Pelton Dam. Moreover, virtually the entire

flow of the Deschutes River at Madras is supported by

ground-water discharge during the summer and early

fall. Ground water and surface water are, therefore,

directly linked, and removal of ground water will

ultimately diminish streamflow.

Analysis of the fluctuations of water-table elevations and ground-water discharge rates in response to

stresses on the ground-water system, such as canal

operation, stream-stage variation, and climate cycles,

indicates that the effects of such stresses are delayed

and attenuated with distance. The effects of groundwater pumping can be expected to be attenuated and

delayed in a similar manner and spread out over time

and space. Depending on the location of a well, several

years may pass between the time pumping starts and

the time the effects of the pumping are reflected in

diminished discharge. It is important to note that the

same physical processes that delay the onset of the

effects of pumping on the streams also cause those

effects to linger after pumping ends. So several years

may also pass between the time pumping stops and the

time the effects on streamflow end.

Presently, the effects of pumping cannot be

measured below the confluence of the Deschutes,

Crooked, and Metolius Rivers. The total consumptive

use of ground water in the upper Deschutes Basin as

of the mid-1990s is estimated to be about 30 ft3/s:

20 ft3/s for irrigations and 10 ft3/s for public water

supplies (assuming 50 percent of public-supply

pumpage is consumptively used). Streamflow at the

Madras gage, which is largely ground-water discharge

during the summer, is about 4,000 ft3/s. Streamflow

measurement techniques used at the gage have an

accuracy of +/– 5 percent, resulting in a range o

of about +/– 200 ft3/s. Because total estimated

consumptive ground-water use is less than 1 pe

of the ground-water discharge at Madras, it is w

within the expected range of measurement erro

amount of ground-water use also is small comp

to the observed natural fluctuations in ground-w

discharge.

Streamflow in the Deschutes Basin fluctua

dramatically at a variety of time scales due to m

factors, including runoff variations, reservoir an

canal operation, and climate cycles. The ground

component of streamflow also fluctuates widely

For example, August mean ground-water disch

the Deschutes River between Bend and Culver 

over 100 ft3/s between 1962 and 1997 due to cl

cycles. The August mean flow of the Crooked R

below Opal Springs, which is mostly ground-w

discharge, varied 460 ft3/s during the same peri

Ground-water discharge to the Metolius River,

based on October mean flows, varied over 400 f

from 1962 to 1997. Combined, these climate-dr

ground-water discharge fluctuations could acco

variations in late-season monthly mean flows of 

Deschutes River at Madras on the order of 1,00

Natural fluctuations of ground-water discharge 

this magnitude in the confluence area totally ma

effects of ground-water withdrawal at present le

development.

Although the effects of historic ground-w

pumping cannot be measured below the conflue

area, the effects of canal leakage are easily disc

in the streamflow records. The August mean flo

the lower Crooked River increased between the 

1900s and the early 1960s by roughly 400 to 50

in a manner that paralleled the increase in estim

canal leakage north of Bend during the same pe

The correlation indicates that a large proportion 

water lost from leaking irrigation canals north o

is discharging to the lower Crooked River upstr

of the Opal Springs gage. This is consistent wit

hydraulic-head distribution and ground-water fl

directions in the area.

Although the effects of historic ground-w

pumping on streamflow cannot be discerned in 

streamflow record below the confluence area, it 

sible that such effects could be measurable on s

streams in the upper Deschutes Basin. Most trib

streams emanating from the Cascade Range, su

Fall River, Squaw Creek, and Indian Ford Creek
75

either spring fed or otherwise hydraulically connected

to the ground-water system. The ground-water discharge to these streams, and consequently streamflow,

could be diminished to a measurable degree depending

on the amount of ground-water pumping and the proximity of pumping to the stream. Long-term streamflow

records, however, are not available to assess possible

effects of historic ground-water development on

smaller streams. Streamflow records are available

for only a small number of tributary streams in the

upper Deschutes Basin, and the gages that are operated

are generally not in locations where the impacts of

ground-water pumping are likely to be detected given

the present geographic pattern of development.

Some stream reaches, for example the Deschutes

River between Bend and Lower Bridge, are perched

above the ground-water system. Although leakage

from such streams can provide recharge to the groundwater system, the rate of leakage is independent of

ground-water elevation changes. Therefore, groundwater pumping will have little or no affect on the rate

of leakage along such reaches.

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This Page Intentionally Blank
Prepared in cooperation with

OREGON WATER RESOURCES DEPARTMENT;

CITIES OF BEND, REDMOND, AND SISTERS;

DESCHUTES AND JEFFERSON COUNTIES;

THE CONFEDERATED TRIBES OF THE

	 WARM SPRINGS RESERVATION OF OREGON;

and U.S. ENVIRONMENTAL PROTECTION AGENCY

Ground-Water Hydrology of the

Upper Deschutes Basin, Oregon

U.S. DEPARTMENT OF THE INTERIOR

U.S. GEOLOGICAL SURVEY

Water-Resources Investigations

	 Report 00-4162
Cover photographs:

Top: Steelhead Falls on the Deschutes River near Crooked River Ranch, Oregon.

Middle: Crooked River Canyon at Crooked River Ranch, Oregon.

Bottom: North and Middle Sister with a wheel-line irrigation system in the foreground

near Sisters, Oregon. (Photographs by Rodney R. Caldwell, U.S. Geological Survey.)