Ground -Water 

Reconnaissance of the 

Santa Barbara-Montecito 

Area, Santa Barbara 

County, California

GEOLOGICAL SURVEY WATER-SUPPLY PAPER 1859-A

Prepared in cooperation with the 

Santa Barbara County Water Agency

Ground -Water 

Reconnaissance of the 

Santa Barbara-Montecito 

Area, Santa Barbara 

County, California

By K. S. MUIR

CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES 

GEOLOGICAL SURVEY WATER-SUPPLY PAPER 1859-A

Prepared in cooperation with the 

Santa Barbara County Water Agency

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1968
UNITED STATES DEPARTMENT OF THE INTERIOR 

STEWART L. UDALL, Secretary

GEOLOGICAL SURVEY 

William T. Pecora, Director

For sale by the Superintendent of Documents, U.S. Government Printing Office 

Washington, D.C. 20402
CONTENTS

Page

Abstract- _________________________________________________________ Al

Introduction. _____________________________________________________ 2

Purpose and scope.----__________----__-___---____-____________ 2

Location and general features.____---_-_-_________--__---_______ 2

Previous investigations and acknowledgments _____________________ 4

Well-numbering system ________________________________________ 4

Geographic features________________________________________________ 4

Climate ______________________________________________________ 4

Landforms and drainage._______________________________________ 5

Lowlands_ ________________________________________________ 5

Bordering mountains._--____-_-__----___-____--_-__-_______ 5

Ground-water resources.___________________________________________ 5

The ground-water reservoir._______--__--_---__-__-_-___________ 5

Geology._________________________________________________ 6

Consolidated rocks___-___---_______--_____-__-________- 6

Unconsolidated deposits._------____________--__________ 9

Santa Barbara Formation._________________________ 9

Casitas Formation.._______________________________ 10

Alluvium. _ _______________________________________ 10

Water-bearing properties ___________________________ 10

Ground-water storage capacity.--__-________________________ 11

Ground-water inventory._______________________________________ 16

Inflow__________________________________________________ 17

Infiltration of rain_____________________________________ 17

Seepage from streams._________________________________ 19

Subsurface inflow from consolidated rocks ________________ 20

Outflow. ____---_---_-___-___---_-_---___--_--------__--__ 20

Pumpage_ _ ___________________________________________ 21

Perennial yield.___________________________________________ 22

Chemical quality._____________________________________________ 25

Sea-water intrusion._______________________________________ 26

Conclusions. ______________________________________________________ 27

References. _______________________________________________________ 28

ILLUSTRATIONS

[Plates are in pocket]

PLATE 1. Map showing major geologic features and location of water

wells, Santa Barbara-Montecito area. 

2. Geologic sections of the Santa Barbara-Montecito area.

m
IV CONTENTS

Page 

FIGUBE 1. Index map showing location of Santa Barbara-Montecitc area. _ A3

2. Map showing ground-water storage units, direction of groundwater movement, and major faults_-__-_-_-_-___-_-__-___ 14

3. Sections showing thickness of storage units____-___-____--___ 15

4. Sketch showing geology and direction of movement of sea

water into the ground-water reservoir- ___________________ 27

TABLES

Page 

TABLE 1. Stratigraphic units of the Santa Barbara-Montecito area______ A7

2. Estimated ground-water storage capacity in the Santa BarbaraMontecito area._______________________________________ 13

3. Estimated recharge in the Santa Barbara-Montecito area by infiltration of rain for the water years (October 1-September 30) 

1868-1964, 1944-64, and 1949-59- _ _.- - -_ - 18
CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES

GROUND-WATER RECONNAISSANCE OF THE SANTA 

BARBARA-MONTECITO AREA, SANTA BARBARA COUNTY,

CALIFORNIA

By K. S. MTJIR

ABSTRACT

This is the third interpretive report prepared by the U.S. Geological Survey 

in cooperation with the Santa Barbara County Water Agency on the groundwater resources of areas along the south coast of the county. The two previous 

reports one by J. E. Upson in 1951 and another by R. E. Evenson, H. D. Wilson, 

Jr., and K. S. Muir were on ground-water conditions in the Goleta ard Carpinteria basins. The Santa Barbara-Montecito area is between those two basins 

the Goleta basin on the west and the Carpinteria basin on the east. This area of 

about 30 square miles extends from the Pacific Ocean on the south to the Santa 

Ynez Mountains on the north. The city of Santa Barbara and the towns of 

Montecito and Summerland are within the area.

The Santa Barbara-Montecito area is a low-lying flat section of the coastal 

plain. Farther inland are highlands of consolidated rock and terrace deposits. 

The highlands are areas of uplift, folding, and faulting, and the lowlands are 

structural depressions. Most of the urban development in the area has been 

in the lowlands. The unconsolidated deposits that have partly filled the structural 

depressions make up the ground-water reservoir of the Santa Barbara-Montecito 

area. They include the Santa Barbara Formation of Pliocene and Pleistocene 

age, the Casitas Formation of Pleistocene age, and the alluvium of late Pleistocene and Recent age. These deposits underlie an area of about 20 square miles 

and have a maximum thickness of about 2,000 feet.

The consolidated rocks of Tertiary age that underlie and form the boundaries 

of the ground-water reservoir contain ground water in fractures and in sandstone beds. However, the consolidated rocks are not an important source of 

ground water.

In 1959, a year the ground-water basins were full and ground water in storage 

was at a maximum, storage in the Santa Barbara area was 184,000 acre-feet, and 

storage in the Montecito area was 97,000 acre-feet. By 1964, in response tc belowaverage recharge and continued withdrawal by pumping, the quantity of ground 

water in storage in the Santa Barbara area had decreased to 178,000 acre-feet. 

Because of a reduction in pumpage, there was little change in storage in the 

Montecito area between 1959 and 1964.

Deep percolation of rain, seepage from streams, and subsurface inflow from 

consolidated rocks are the main sources of recharge to the ground-water reservoir 

in the Santa Barbara-Montecito area.The most important discharge is by pumping.

Al
A2 CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES

The long-term perennial yield of the ground-water reservoir of the Santa 

Barbara area is estimated to be 1,700-2,000 acre-feet. Present data are insufficient to accurately determine the perennial yield of the reservoir in the Montecito 

area, but it is estimated to be about 2,500 acre-feet.

Most ground water in the Santa Barbara-Montecito area is suitable for general 

use. However, ground water in some of the consolidated rocks and in the shallow 

unconsolidated deposits adjacent to the coast is too saline for most uses. Seawater intrusion has occurred in the Santa Barbara area and the western part of the 

Montecito area. The intrusion, however, is limited to the upper part of the nearshore shallow alluvial deposits and contaminates only wells which were constructed 

without a near-surface seal.

INTRODUCTION 

PURPOSE AND SCOPE

The Santa Barbara County Water Agency is making plans to 

insure sufficient water for the future needs of the county. A knowledge 

of the hydrologic conditions in the county, therefore, is necessary. 

The purpose of this report is to provide hydrologic infcrmation for 

the Santa Barbara-Montecito area (fig. 1).

The scope of this investigation includes a study of the geology of 

the area, with particular reference to the water-bearing deposits, a 

determination of the areal extent and thickness of the ground-water 

reservoir, the quantity and chemical quality of water in storage, and, 

as data permit, inflow to and outflow from the aquifers in the area.

The investigation was made by the U.S. Geological Survey, in 

cooperation with the Santa Barbara County Water Agenc;T , under the 

general supervision of Walter Hofmann, district chief in charge of 

water-resources investigations in California, and under the immediate 

supervision of L. C. Dutcher, chief of the Garden Grove subdistrict.

LOCATION AND GENERAL FEATURES

The Santa Barbara-Montecito area is on the south coast of Santa 

Barbara County (fig. 1, pi. 1) between two ground-water basins 

the Goleta basin on the west and the Carpinteria basin on the east. 

It is predominantly an urbanized area of about 30 sauare miles, 

extending from the Pacific Ocean on the south to the foothills of the 

Santa Ynez Mountains on the north. The city of Santa Barbara and 

the towns of Montecito and Summerland are the major population 

centers. Lemon growing near Montecito and Summerland is the 

primary agricultural activity.

The water supply for the Santa Barbara-Montecito are«, is obtained 

from two sources: Ground water pumped from local wells and surface 

water impounded behind dams on the Santa Ynez River. The impounded water is delivered to users along the south coast by three 

tunnels cut through the Santa Ynez Mountains.
120°30' 120°00' 

35°00'

34° 30'

Point Conception

0 '4 SMILES

FIGURE 1. Index map of Santa Barbara County showing the S
A4 CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES 

PREVIOUS INVESTIGATIONS AND ACKNOWLEDGMENTS

This is the third interpretive report describing the ground-water 

resources of areas along the south coast of Santa Barbara County. 

The two previous reports described the Goleta and Carpinteria basins 

(Upson, 1951; Evenson and others, 1962).

The cooperation and assistance of the city of Santa Barbara Water 

Department, the Montecito County Water District, and the Southern 

California Edison Co. in supplying data on water levels, pumpage, 

and chemical quality of ground water are gratefully acknowledged.

WELL-NUMBERING SYSTEM

Wells and springs are numbered according to the rectangular 

system of subdivision of public land. Where the land has not actually 

been surveyed, appropriate subdivisions are projected. A well number, 

such as 4N/27W-15R1, has two parts. The part that precedes the 

hyphen indicates the township and range (T. 4 N., R. 27 W.). The 

numbers following the hyphen indicate the section (sec. 15); the letter 

indicates the 40-acre subdivision of the section, as shown in the accompanying diagram; and the final number is the serial number in the 

particular 40-acre tract. Accordingly, well 4N/27W-15R1 is the first 

well listed in the SE% SE% sec. 15, T. 4 N., R. 27 W., San Bernardino 

meridian and base line.

D

E

M

N

C

F

L

P

B

G

K

Q

A

H

J

R

GEOGRAPHIC FEATURES

CLIMATE

The Santa Barbara-Montecito area has distinct wet and dry seasons. 

About 95 percent of the rainfall occurs between November and May. 

The average rainfall at Santa Barbara, based on 97 years of record, 

is 17.79 inches. The rainfall pattern is not uniform; the bordering 

foothills receive more rain than the low-lying coastal area. Troxell and 

others (1942, p. 48-49) estimated that along the coast of southern 

California rainfall increases 3 inches for each 1,000-foot increase in 

altitude. Nearly all ground-water recharge and surface-water flow in 

the Santa Barbara-Montecito area are derived from rain that falls
GROUND WATER OF SANTA BARBARA-MONTECITO, CALIF. A5

directly on the area. However, a small part of the imported water 

from the Santa Ynez River may recharge the ground water.

Seasonal temperatures are moderate. Winter temperatures average 

55°F; summer temperatures, 65°F. There is little or no frost during 

the winter months.

Fog and high humidity are common in the morning during the 

summer months. Winds, which usually blow from the west or southwest, normally dissipate the fog by midday.

LANDFORMS AND DRAINAGE 

LOWLANDS

The Santa Barbara-Montecito area (pi. 1) consists of a low-lying, 

nearly flat alluviated plain and the adjacent highlands. The lowlands 

are underlain by unconsolidated deposits that range in thickness 

from several hundred to several thousand feet; the highlands are 

underlain by consolidated rock and terrace deposits. The main part of 

the city of Santa Barbara is in the western part of the low-lying- plain, 

and the town of Montecito is in the eastern part.

Seven main creeks carry runoff from the area. These creeks, where 

they flow across consolidated rocks in their headwater reaches-, have 

gradients of about 800 feet per mile. The gradients decrease where 

the stream courses reach areas underlain by alluvium, but even there 

the gradients are steep about 200 feet per mile. The stream gradients 

conform closely to the land-surface gradients across the lov-lying 

areas. Several of the creeks are perennial in their upper reaches, but 

all are intermittent where they cross the alluvium.

BORDERINQ MOUNTAINS

The Santa Ynez Mountains, which adjoin the area on the north, are 

made up of a series of complexly folded and faulted consolidated rocks 

of Tertiary age. They rise steeply from the edge of the coastal plain, 

and several miles inland have altitudes of nearly 4,000 feet above sea 

level.

Erosion has formed deep gulleys and sharp ridges and has left little 

or no soil to mantle the mountains. Brush and grass are the principal

ground cover.

GROUND-WATER RESOURCES

THE GROUND-WATER RESERVOIR

In the Santa Barbara-Montecito area there is close similarity 

between geologic structure and topography: Mission Ridge, the 

Summerland area, and La Mesa have been uplifted along faults 

(pi. 1); the central part of the city of Santa Barbara and the Montecito 

area are in structural depressions. The unconsolidated deposits that

288-767 68 2
A6 CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES

partly fill these structural depressions form the ground-water reservoir 

of the Santa Barbara-Montecito area. The deposits include the Santa 

Barbara Formation, the Casitas Formation, and alluvium ranging 

in age from Pliocene to Kecent (pis. 1 and 2). These deposits underlie 

an area of about 20 square miles and have a maximum thickness of 

about 2,000 feet along the north sides of the Lavigia and Mesa faults.

The consolidated rocks that underlie and form the boundaries of 

the ground-water reservoir contain ground water in fractures and in 

sandstone beds. However, these formations yield ground water to 

wells slowly and are important mainly as a source of recharge by 

subsurface flow to the unconsolidated deposits.

The crustal movements that formed the structural degressions in 

the Santa Barbara and Montecito areas began in late Pliocene time. 

Folding and faulting at that time created basins in which detrital 

material eroded from adjacent highlands subsequently was deposited. 

This detrital material makes up the Santa Barbara and Casitas Formations, which are the major aquifers of the ground-water reservoir 

(pi. 2). The Santa Barbara Formation was deposited in a marine environment; the Casitas Formation, in a nonmarine environment.

In middle or late Pleistocene time, renewed crustal movements 

once again caused uplifting, faulting, and folding of the consolidated 

rocks. At the same time, vertical movements along the faults in some 

areas displaced the Santa Barbara and Casitas Formations several 

thousand feet (pi. 2). The general boundaries of the ground-water 

basins of the area were established by these movements.

Since middle Pleistocene time several advances and retreats of the 

ocean, caused both by worldwide changes of sea level anc1 by crustal 

movements, have occurred, as have renewed movements along the 

preexisting faults. The deposition of alluvium and the formation of 

terraces accompanied these events.

GEOLOGY

In this report, the geologic formations are divided into two groups: 

The consolidated rocks of Tertiary age and the unconsolidated deposits 

of Quaternary age. This division is based on water-bearing properties. 

The consolidated rocks, represented on the geologic map and geologic 

sections (pis. 1 and 2) as one unit, are important mainly because they 

delineate the boundaries of the unconsolidated deposits.

Plate 1 shows the outcrop pattern of the formations; plate 2 shows 

their stratigraphic and structural relations; and table 1 summarizes 

their sequence, general character, and water-bearing properties.

CONSOLIDATED ROCKS

Consolidated rocks of Tertiary age underlie the Santa Barbara 

Formation (pi. 2). They have been uplifted to form the prominent
GROUND WATER OF SANTA BARBARA-MONTECITO, CALIF. A7 

TABLE 1. Stratigraphic units of the Santa Barbara-Montecito area,

Period

>H

Pj

(2;

tf

f-i

L>oQ

^ri ^3^^

>H £

PJ Pjj

K H

PH [D

c^ "

Epoch

-4-=

d

0)

0 

0)

tf

0)

Q) 

U

O-4-2

JS5

Q) d

Q)

U 

1

£

73

i

d

§

£

 

Formation

Alluvium. Includes

younger alluvium, older

alluvium, and

terrace deposits, undifferentiated.

Unconformity

Casitas

Formation

Santa Barbara

Formation

TTnr»nnfnTmitv

General character

Unconsolidated

gravel, sand, silt,

and clay. Underlies the alluvial

plains and extends into adjoining stream

canyons. Marine

terraces are found

along the seaward

side of La Mesa

and at Summerland.

Unconsolidated

yellow-brown to

red gravel, sand,

silt, and clay.

Also contains

some cobbles and

boulders. It is

continental in

origin. The formation probably

underlies part of

the Montecito

area. It crops out

at Summerland

and near the

Santa Barbara

cemetery.

Unconsolidated

gravel, brown

sand, silt, and

clay, with discontinuous conglomerate beds at

the base. Also

includes a few

calcareous clay

beds. The formation is marine

in origin and

fossiliferous. It

underlies most of

the area.

Water-bearing

properties

Alluvium is

permeable

and yields

moderate

quantities of

water to

wells. Terrace

deposits are

above zone of

saturation,

and contain

little vater.

Yields moderate

quantities of

water to wells.

Yields moderate

quantities of

water to wells.

It is the major

aquife" of the

area.
A8 CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES 

TABLE 1. Stratigraphic units of the Santa Barbara-Montecito area Continued

Period

k*

PH

EH 

PH

EH

Epoch

0>

s

O> 

0

.2

^

O> Pi 8

0

o

W

Formation

Sedimentary

rocks. Include

Monterey

Shale, Rincon Shale,

Vaqueros

Sandstone,

Sespe Formation, and

Tejon Formation, undifferentiated.

General character

Consolidated sandstone, siltstone,

mudstone, and

shale. The formations are both

continental and

marine in origin.

They underlie

the entire area.

Pyroclastic material, conglomerate, and limestone occur

interspersed

throughout the

deposits.

Water-bearing 

properties

YieM water

from fractures

and from

sandstone

units. The

water-bearing

properties of

these formations are

largely unknown.

highlands of La Mesa, of Mission Ridge, and of the Snmmerland 

area. These rocks form continuous outcrops in the foothills of the 

Santa Ynez Mountains (pi. 1). The consolidated rocks aho crop out 

on the ocean floor about a quarter of a mile offshore east of Stearns 

Wharf. The outcrop extends to an area east of Fernald Point (pi. 1). 

Uplift has probably occurred along an east-west-trending fault in 

this area.

The consolidated rocks, which range in age from Eocene to Miocene, 

are sedimentary rocks predominantly marine in origin. From oldest 

to youngest, they are the Tejon Formation, the Sespe Formation, 

the Vaqueros Sandstone, the Rincon Shale, and the Monterey Shale. 

The base of the Tejon Formation is not exposed in the mapped area, 

so its relation to the underlying rocks is unknown. An ur conformity 

exists between the consolidated rocks of Tertiary age and the overlying unconsolidated younger deposits.

The total thickness of the consolidated rocks is about 15,200 feet 

two-thirds consists of shale, mudstone, and siltstone, and one-third 

is composed predominantly of sandstone. Pyroclastic material, conglomerate, and limestone are interspersed through the deposits. Fossils 

are common in the marine beds.

The consolidated rocks in the Santa Barbara-Montecito area are 

water bearing. Ground water is contained in the fractures and in 

the sandstone units. However, the rocks are not considered a good 

source of ground water because the occurrence and location of the
GROUND WATER OF SANTA BARBARA-MONTECITO, CALIF. A9

fractures in the more consolidated parts of the rocks are difficult 

to determine, and the sandstone units have low specific yields and 

release ground water to wells slowly.

Direct evidence of ground water in the consolidated rocks is found 

in the seepage from unlined parts of tunnels which penetrate thick 

sections of these rocks in the Santa Ynez Mountains (fig. 1). Groundwater seepage into Mission Tunnel, through which surface water 

stored behind Gibraltar Dam on the Santa Ynez River is brought 

to the city of Santa Barbara, is about 1,000,000 gpd (gallons per 

day). This tunnel has a total length of 19,560 feet, of which 9,800 

feet is unlined. Doulton Tunnel, through which surface water is 

brought from Juncal Dam to the Montecito area, has a groundwater inflow of 300,000 gpd through an unlined 7,000-foot section 

of the tunnel. Cold Springs Tunnel (pi. 1) was excavated by the 

city of Santa Barbara specifically to develop a source of water from 

the consolidated rocks. This tunnel, 3,300 feet of which is unlined, 

penetrates 5,000 feet of sandstone and shale, and the flow averages 

about 120,000 gpd.

Data furnished by the city of Santa Barbara indicate that groundwater inflow to the tunnels responds to the long-term variation of 

the rainfall more inflow during wet periods and less during dry 

periods.

A few wells in the area obtain water from the consolidated rocks 

and have small yields and large drawdowns. Well 4N/27Yr-20El 

penetrated 380 feet of the Vaqueros Sandstone and was perforated 

through an interval of 200 feet; it yielded 175 gpm (gallons per 

minute) with a drawdown of 350 feet. The pumping level in this 

well stabilized at 70 feet below the land surface when a pumping 

rate of 75 gpm was maintained.

UNCONSOIIDATED DEPOSITS

SANTA BARBARA FORMATION

The Santa Barbara Formation underlies most of the Santa larbaraMontecito area. This formation, of Pliocene and Pleistocene age 

(Woodring and others, 1940, p. Ill), is composed of massive unconsolidated brown marine sand, silt, and clay (pi. 2). The sand consists 

of medium-grained well-rounded quartz with some inte^bedded 

conglomerate and calcareous clay. There is an extensive outcrop of 

calcareous clay in sec. 20, T. 4 N., R. 27 W.

The Santa Barbara Formation lies unconformably on the consolidated rocks of Tertiary age and in most of the area underlies the alluvium. In the Montecito area, however, the Santa Barbara Formation 

grades upward into the Casitas Formation of Pleistocene ag?. (State 

of California, 1954).
A10 CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITFD STATES

The Santa Barbara Formation has a maximum thickness of about 

2,000 feet on the north side (downthrown side) of the Lr.vigia fault 

in sec. 20, T. 4 N., R. 27 W., and on the north side (downtl rown side) 

of the Mesa fault in sec. 22, T. 4 N., R. 27 W. It thins toward the 

north. Beneath the central part of the city of Santa Barbara (pi. 2) 

the formation is about 400-500 feet thick.

CASITAS FORMATION

The Casitas Formation, of Pleistocene age, underlies part of the 

Montecito area. It consists mainly of unconsolidated continental 

deposits of generally yellowish-brown to red gravel, sand, silt, and clay, 

but cobbles and boulders also occur.

The Casitas Formation has a gradational contact with tH underlying Santa Barbara Formation and is unconformably overlain by the 

alluvium. It is not present beneath the city of Santa Barbara and crops 

out only at Summerland and near the Santa Barbara cemetery (pi. 1). 

It has a maximum thickness of about 500 feet.

ALLUVIUM

The alluvium, as mapped, includes the terrace deposits, older alluvium, and younger alluvium of Upson (1951, p. 24-25). It rests 

unconformably on all older deposits and consists of gravel, sand, silt, 

and clay, of late Pleistocene to Recent age. Cobbles and boulders 

occur throughout the deposits (pi. 2) which are extensive over most 

of the area. The maximum thickness is about 500 feet.

WATER-BEARING PROPERTIES

The Santa Barbara Formation, the Casitas Formation, and the alluvium have similar water-bearing properties. All three have vertical 

variations in lithology in which coarse-grained beds that yield water 

freely to wells alternate with fine-grained beds that do not. Good 

yields can be obtained only from those wells that penetrate many of 

the coarse-grained beds. Consequently, most wells are perforated in 

all the saturated coarse-grained deposits that are penetrated, down to 

and including those of the Santa Barbara Formation.

Ground water in the Santa Barbara Formation, Casitas Formation, 

and alluvium is locally under artesian pressure. Several wells flowed 

in 1963; well 4N/27W-15Q8 flowed at a rate of about 2 gpm, and well 

4N/26W-8P2 flowed at a rate of 15-20 gpm. Pumped yields of 500- 

1,000 gpm and specific capacities of 3-6 gpm per foot of drawdown 

are common.

The electric logs on plate 2 graphically illustrate variations in 

the water-bearing characteristics of the deposits in the Santa BarbaraMontecito area: a high resistivity on electric logs of the^e deposits 

indicates coarse-grained water-bearing beds, and a low resistivity
GROUND WATER OF SANTA BARBARA-MONTECITO, CALIF. All

indicates fine-grained beds. Plate 2 shows that beneath the city of 

Santa Barbara, within the alluvium, there are two water-bearing 

zones distinct enough to permit delineation, each about 50 feet 

thick, with the upper zone at a depth of about 250 feet below sea 

level and the lower zone at about 350 feet below sea level. Plate 2 

shows (1) that in addition to the two distinct water-bearing zones 

shown on plate 2, there are other water-bearing beds with interspersed fine-grained deposits; (2) that the lithology of the alluvium 

and Santa Barbara Formation are similar; (3) that the Santa Farbara 

Formation seems to have a coarse-grained basal zone; and (4) that 

in general the water-bearing deposits underlying the Montecito area 

(pi. 2) are coarser grained than those underlying the city of Santa 

Barbara. Data are insufficient to permit a delineation of any continuous 

water-bearing zones in the Montecito area.

GROUND-WATER STORAGE CAPACITY

Ground water is stored in the interstices of the unconsolidated 

deposits of the alluvium, Casitas Formation, and Santa Farbara 

Formation. The interstices are filled with water below the zone of 

saturation; the quantity of water contained depends upon the porosity 

of the deposits. However, the quantity of water in the pore spaces 

and the quantity that will be released to wells are not everywhere 

equal. Only the water that will drain from the pore spaces by gravity 

is available for use. The specific yield of a rock or soil with respect 

to water has been defined by Meinzer (1923, p. 28) as the ratio of 

(1) the volume of water which, after being saturated, it will yield 

by gravity to (2) its own volume. The water that remains in the pore 

spaces after gravity drainage is held there mainly by surface tension. 

The total quantity of ground water in storage that is available for 

use by man (storage capacity) is equal to the volume of saturated 

material times its specific yield.

To compute the storage capacity of the water-bearing deposits, 

the area was divided into five storage units as shown in figure 2. 

The boundaries of these storage units are in part determined by 

faults that impede the movement of ground water. Higher water 

levels usually occur on the upgradient sides of the faults thai on the 

downgradient sides.

The western boundary of storage unit 2 and the boundary l^tween 

storage units 1 and 4 are formed by ground-water divides. The city 

of Santa Barbara overlies most of storage units 1, 2, and 3, and the 

Montecito area overlies storage units 4 and 5. The surface areas of 

the five storage units are listed in table 2. The arrows in figure 2 

show the direction of ground-water movement southward toward 

the ocean.
A12 CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES

After dividing the area into storage units, the saturated material 

in each unit was assigned a value for specific yield based on the 

classification by Evenson and others (1962) for the adjacent Goleta 

and Carpinteria basins. This classification is summarized in the 

following table.

Types of material according to drillers' terms

Gravel, gravel and sand, boulders

Sand, fine sand _ _

Silt, packed sand, hard sand, sandy 

clay; soil. 

Clay and gravel, hard sand and 

gravel, cemented gravel.

Assigned classification

Gravel.

Sand

Sand and clay_ 

Clay and gravel- __ 

Clay_____________

Assigned specific 

yielc" (percent)

25

20

7 

5 

1

Generally, in ground-water basins adjacent to the ocean, storage 

computations are limited to zones above sea level because of possible 

sea-water intrusion if ground-water levels decline to or below sea 

level. However, in the Santa Barbara-Montecito area, usable storage 

in the deposits below sea level can be computed because ar east-westtrending fault just offshore (pis. 1, 2; figs. 2, 3) acts as £,n effective 

barrier to the movement of sea water into the lower part of the freshwater aquifers under present hydrologic conditions. The estimated 

storage capacities of the units given in table 2 and showr in section 

in figure 3 are conservative because only a minimum thickness of 

saturated deposits is used. The saturated thickness used is the interval 

between the highest recorded static ground-water level and the lowest 

recorded pumping level the zone of maximum recorded water-level 

fluctuation. In figure 3 the top of each unit represents the highest 

recorded static water levels within the unit, and the bottom of each 

unit represents the lowest recorded pumping levels within the unit. 

Ground-water storage estimates were limited to this one zone because 

under present pumping demands no draft will occur in any lower 

zones in the foreseeable future.

In calculating the volume of storage capacity available, the saturated thickness of each unit was divided into a series of depth zones, 

and an average specific yield for each zone was computed. The 

storage units were divided into these depth zones tc facilitate 

future storage-change calculations. The ground-water storage capacity 

in each zone was computed by multiplying the average specific 

yield of the zone by its volume. Table 2 lists the ground-water storage 

capacity in each depth layer within the different storage units, the 

storage capacity for each unit, and the total capacity of all five
TABLE 2. Estimated ground-water storage capacity in the S

Storage unit

Depth zone (in feet above or 

below sea level)

Surface area of 

depth zone 

(acres)

Volume of 

depth zone 

(acre-ft)

Weig

average 

yield o

zone (p

Santa Barbara area 

1

2 _________ _________

3 .

Subtotal -__._ _

-50 to -100_ - ._..__ _ ------

-100 to -200 ---- _____ _

+100 to +50 - . 

-100 to -200 _ _ _ 

-50 to 100

» 2, 040 

4.200 

4,200 

4,200 

1,700 

1,700 

1,700 

1,700 

1.700 

1 1,270 

2,000 

2,000

102, 000 

210, 000 

210, 000 

420,000 

85,000 

85,000 

85, 000 

85,000 

170, 000 

63,500 

100, 000 

100,000

Montecito area 

5

Total ________

Sea level to -50--... ___ - __

-50 to -100 _________- _

-100 to -150 - _ _- 

2,000 

2,000 

2,000 

2,300

100,000 

100, 000 

100, 000 

575,000
R. 27 W. 

Direction of 

ground-water 

movement

FIGURE 2. Ground-water storage units, direction of ground-water movement, 

and storage of ground water. Sections shown 
vxxvs 'oiioaiNOw-vHvaHva eiv
A16 CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES

storage units, which also was the ground water in storage for 1959 a 

year for which ground-water storage was at a maximum throughout 

most of the area.

Ground water in storage units 1, 2, and 3 is available for use by 

wells in the area of the city of Santa Barbara (fig. 2). In 1959 the 

ground water in storage in this area was about 184,000 acre-feet. 

By 1964, in response to below-average recharge and continued withdrawal, a decline of water level indicated the quantity of ground 

water in storage had decreased to about 178,000 acre-feet, which is 

the lowest on record.

In the Montecito area wells pump ground water from storage units 

4 and 5, and in 1959 ground water in storage was about 97,000 acrefeet. There was very little change in storage between 1959 and 1964.

GROUND-WATER INVENTORY

The hydrologic equation states that all water that enters an area 

during any period of time must, during the same period, either go 

into storage, be evaporated therefrom, be exported therefrom, or 

flow out either on the surface or underground. If, as in this report, 

the hydrologic equation is applied only to the inflow and outflow of 

a ground-water basin, it is called a ground-water inventory. A groundwater inventory is just what the term implies it is the inventory 

of all items of inflow and all items of outflow for a ground-water 

basin. An analysis of the inventory makes it possible to estimate 

perennial yield and allows those responsible for the management of 

a ground-water basin to plan the future use of the water resources.

The first step in making a ground-water inventory is to select 

the time span for the inventory. The period selected should reflect 

average long-term climatic conditions. In the Santa Barbara-Montecito area the periods selected were (1) 1868 to 1964, (2) 1944 to 

1964, and (3) 1949 to 1959. The first period represent?1 long-term 

climatic conditions, the second spans a prolonged period of generally 

less than average rainfall (a time of minimum inflow), and the third 

covers a period when there was little or no change in tbe quantity 

of ground water in storage (inflow equaled outflow over the 11-year 

period) within the basin.

Pertinent items of the ground-water inventory are listed below.

Inflow

Infiltration of rain. 

Seepage from streams. 

Subsurface inflow from consolidated rocks. 

Water imported from the Santa Ynez River. 

Infiltration of irrigation water.
GROUND WATER OF SANTA BARBARA-MONTECITO, CALIF. A17

Outflow 

Pumpage.

Subsurface discharge to ocean. 

Evapotranspiration.

INFLOW

Infiltration of rain, seepage from streams, and subsurface inflow 

from consolidated rocks are the main items of inflow into the groundwater basin. Water imported from the Santa Ynez River by diversion 

through the Mission, Tecolote, and Doulton Tunnels supplies nearly 

all the municipal water for the Montecito area and the majority 

of the municipal water for the city of Santa Barbara. Little of this 

water enters into the ground-water inventory because it is s, piped 

supply which, after use, is discharged to the ocean as sewage. About 

700-750 acres, primarily in citrus, is irrigated with imported water. 

There is some inflow into the ground-water basin from infiltration 

of irrigation water, but the quantity is small about 150 acre-feet 

per year (50 acre-feet in the Santa Barbara area and 100 in the 

Montecito area).

INFILTRATION OF RAIN

The major source of recharge to the ground-water reservoir in the 

area is infiltration of rain that falls directly on areas of unconscUdated 

deposits (pi. 1). Measurements and work by Blaney (1933) in neighboring Ventura County were used in this study to estimate the quantity of rain that becomes ground water. Climate, soils, geology, and 

vegetative cover in the two areas are similar. Blaney tabulated the 

quantities of rain that became ground water, depending upon type of 

vegetative cover and seasonal precipitation, for several locations in 

Ventura County for a period of 5 years. Upson (1951, p. 63, fig. 2), 

using Blaney's data, graphically related seasonal rainfall to depth of 

penetration on lands covered with several different types of vegetation. 

Infiltration of rain on the Santa Barbara-Montecito area was estimated 

from the curves shown on Upson's graph.

The area of infiltration of rain includes storage units 2, 4, and 5 

(fig. 2). It includes also that part of storage unit 1 that lies above an 

altitude of 250 feet above sea level and that part of storage unit 3 

that lies above an altitude of 100 feet. Below those altitudes, storm 

sewers, city streets, and buildings prevent significant infiltration of 

rain. In the Santa Barbara area (storage units 1, 2, and 3), the infiltration area includes about 3,400 acres, of which 1,300 acres is covered 

with grass and weeds and 2,100 acres with a citrus-type ccver. In 

the Montecito area (storage units 4 and 5) there are 4,300 acres, all 

with a citrus-type cover. The areas classified as having a citrus-type 

cover are those that have a scattering of citrus trees, lawns, home
A18 CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES

gardens, avocado trees, and miscellaneous deciduous trees; only about 

200 acres in the Santa Barbara area and about 550 acres in the 

Montecito area are planted in commercial citrus groves.

The rainfall recorded at Santa Barbara was used in estimating 

infiltration from rain. The rainfall that infiltrated in the Santa BarbaraMontecito area for the periods 1868-1964, 1944-64, and 1949-59 is 

given in table 3.

TABLE 3. Estimated recharge, in acre-feet, in the Santa Barbara-Montecito area by 

infiltration of rain for the water years (October 1-September SC) 1868-1964, 

1944-64, and 1949-59

Period

1868-1964 .... 

1944-64......

1949-59......

Average rainfall at Santa 

Barbara 

(inches)

17.79 

15.55 

16.96

Land In grass and 

weeds

Santa Barbara area 

(1,300 acres)

Total 

recharge

17,680 

2,360 

1,810

Average 

yearly 

recharge

180 

110 

160

Land with citrus-type cover

Santa Barbara area 

(2,100 acres)

Total 

recharge

87,200 

12,820 

8,680

Average 

yearly 

recharge

900 

610 

790

Montecito area 

(4,300 acres)

Total 

recharge

178, 750 

26, 340 

17, 780

Average 

yearly 

recharge

1,840 

1,250 

1,620

Total average 

yearly 

recharge

2,900 

2,000 

2,600

The Santa Ynez foothills, an area of brush-covered consolidated 

rocks, including 8,600 acres near Santa Barbara and 7,500 acres near 

Montecito, is a secondary area of infiltration. The infiltration on 

these brushlands is estimated, on the basis of Blaney's (1933) work, 

to be 10 percent of the amount of rain greater than 18 inches.

The rainfall used in these calculations is that recorded at Santa 

Barbara, plus an estimated additional 3 inches per 1,COO feet in 

altitude (Troxell and others, 1942, p. 48 and 49, fig. 5). The average 

altitude of this brushland is about 1,700 feet above sea level.

The following table lists the estimated average yearly infiltration 

from rain on brushlands for the three selected periods of time:

Because some of the infiltration on brushland is stored in the 

fractures and sandstone beds of the consolidated rocks, the quantity 

recharging the ground-water reservoir was not included in the estimate of total inflow used elsewhere in this report.

Period

Average yearly infiltration, in acre-feet, of rain on bruf hlands

1868-1964_ ______

!944-64____ _ __

1949-59_ ________

Santa Barbara area

360

260

350

Montecito area

310

230

300

Total

670

490

650
GROUND WATER OF SANTA BARBARA-MONTECITO, CALIF. A19 

SEEPAGE FROM STREAMS

In the Santa Barbara-Montecito area seepage occurs along the 

lower reaches of the streams in the areas where they flow across 

unconsolidated deposits (pi. 1). Where streams flow across consolidated rocks, the steep stream gradients and the flash-flow characteristics of the streams prevent large seepage losses.

Seepage loss from streams is usually estimated from the decrease 

in streamflow between two gaging stations. The establishment of 

gaging stations on all creeks in the area was not economically feasible; 

therefore, indirect methods were used to estimate runoff and seepage 

loss.

Streamflow data collected from San Jose Creek in the adjacent 

Goleta basin were used to estimate runoff in the Santa BarbaraMontecito area. San Jose Creek was chosen because the stream has 

been gaged continuously since 1941, because the stream-gaging site 

is near the contact between the consolidated rock and the unconsolidated deposits, because the drainage area is underlain Vy consolidated rocks, and because the stream gradient (about 700 ft per 

mile) and the altitude of the drainage area are similar to those of 

streams in the Santa Barbara-Montecito area. The streamflow 

characteristics probably are also similar. Thus, runoff measured at 

the present gaging site on San Jose Creek should be a good index 

of the expectable runoff (dependent upon drainage area) from areas 

of consolidated rock along the Santa Barbara-Montecito part of the 

south coast of Santa Barbara County; that is, of the quantity of 

surface water that is available for seepage from the streams.

The runoff from each stream in the Santa Barbara-Montecito area 

was estimated by using the drainage area-runoff ratio from the San 

Jose Creek drainage basin. Near Santa Barbara, runoff occurs in a network of streams which drain San Roque, Barger, Mission, Lauro, Rattlesnake, and Sycamore Canyons. The combined drainage-barm area 

of these streams in the area of consolidated rock is about 14 square 

miles. Near Montecito, streams in Cold Spring, Hot Spring, San 

Ysidro, Romero, and several unnamed canyons have a combined consolidated rock drainage area of about 12.5 square miles. San Jose 

Creek has a drainage basin of 5.5 square miles. Stream runoff from 

the drainage areas adjacent to Santa Barbara and Montecito is assumed for each area to be about 2.5 times that of San Jose Creek.

Seepage-loss estimates in the Santa Barbara-Montecito area are 

based on ground-water recharge data for the adjacent Carpinteria 

and Goleta basins (Thomasson, in Upson, 1951, p. 43-45, 51-53; 

Evenson and others, 1962, p. 54, 92). Data from those basins are considered to be applicable for extrapolation and use in the Santa Barbara-
A20 CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES

Montecito area, and they indicate that seepage from streams averages 

about 14 percent of the runoff.

The following table lists the average yearly recharge (calculated 

on the basis of the assumptions described above) from seepage in 

the area during the two selected periods for which streamflow data 

were available.

These estimates of ground-water recharge are based only on estimates of runoff from the areas of consolidated rocks and are conservative. Some runoff undoubtedly originates in areas underlain by 

unconsolidated deposits and eventually percolates to ground water, 

but the quantity cannot now be estimated.

Period

1944-64. ________

1949-59. ________

Average yearly recharge, in acre-feet, from seepage loss in the Santa 

Barbara-Monteclto area

Santa Barbara area

360 

450

Montecito area

360 

450

Total

720 

900

SUBSURFACE INFLOW FROM CONSOLIDATED ROCKS

There is subsurface inflow from the consolidated rocks that form 

the boundary of the ground-water reservoir in the Santa BarbaraMontecito area. The quantity cannot be determined directly. A 

relation probably exists, however, between water levels and inflow 

from the consolidated rocks. When water levels are high in the groundwater basin, inflow from the consolidated rocks probably decreases 

slightly; conversely, when water levels are low, inflow probably increases slightly. Indirect estimates, based on the ground-water 

inventory for the period 1949-59 during which quantities of ground 

water in storage did not change, suggest that subsurface inflow to 

the Santa Barbara area from the consolidated rocks is about 300 

acre-feet per year. Data are not available for a similar estimate for 

the Montecito area. However, it probably is about the same as in 

the Santa Barbara area 300 acre-feet per year.

OUTFLOW

Of the items of outflow, pumpage is the most important. Subsurface 

discharge to the ocean probably is small because ground-water levels
GROUND WATER OF SANTA BARBARA-MONTECITO, CALIF. A21

adjacent to the coast are, and have been in the past, at or near sea 

level, resulting in nearly flat ground-water gradients toward the 

ocean. Evapotranspiration is also small. Water levels in most places 

are too deep (more than 20 ft below land surface) for transpiration 

of ground water to be effective. Where water levels are closer to the 

land surface, the area is either covered by urban structures or all 

native vegetation has been removed.

PUMPAQE

Withdrawal of ground water by pumping from wells is the major 

outflow from the ground-water reservoir in the Santa BarbaraMontecito area. All other forms of outflow are insignificant.

Withdrawal of ground water from wells began to supplement local 

surface-water sources in the early 1800's. These local surface-water 

supplies varied considerably from year to year in direct relation to 

the rainfall. Water shortages always followed winters of low rainfall. 

In an attempt to develop a more dependable source of water, wells 

were drilled. Later it became obvious that local sources of water 

would not be sufficient to supply the demands of an expanding 

population. With this realization, surface-water supplies were 

developed by building several dams on the Santa Ynez River (fig. 1). 

Today, Juncal, Gibraltar, and Cachuma Dams impound water which 

is supplied to users in the area.

However, even now during years of low rainfall, all sources of 

surface water are heavily drawn upon and water is in short supply. 

During such drought years, water users depend heavily on groundwater supplies. The city of Santa Barbara and the Montecito County 

Water District have wells on which they rely to avoid water shortages 

during drought years. The Montecito County Water District uses 

its water wells only when the surface-water supplies are low. On 

the other hand, in recent years the city of Santa Barbara has been 

using more and more ground water. The city has done this, not so 

much to supplement the surface-water supply, but to utilize an 

available local source of low-cost ground water.

The following table lists the quantity of ground water pumped 

by the city of Santa Barbara and the Montecito County Water 

District for 1947-64. No records are available for years prior to 

1947. Pump age shown for each individual year is the amount of 

water pumped during the 12-month period beginning May 1.
A22 CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES 

Municipal pumping in the Santa Barbara-Montecito area, 1947-64

Year

1947.. .-..___...____..

1948

1949

1950

1951________ _____ _ _

1952 . _

1953--___- _______

1954________ _____ ___

1955__ _ _

1956-. ___ _ _

1957______ ______

1958

1959__ _____ ___ _ ...

I960. __ _ _____

1961

1962______ _ _____ _

1963

1964__ _____ ___

City of Santa 

Barbara

336

3,471

4,243

3,987

2,745

1,002

1,497

891

413

220

1,480

81

81

2,961

2,961

2, 535

2,941

2,888

Pumpage (acre-ft)

Montecito County 

Water District

76

298

407

450

108

82

179

102

102

34

37

0

18

0

0

0

0

0

Total '

410

3,770

4,650

4,440

2,850

1,080

1,680

990

520

250

1,520

80

100

2,960

2,960

2,540

2,940

2,890

1 Rounded to the nearest 10 acre-ft.

The quantity of water pumped for irrigation, domestic, stock, 

and industrial uses in the Santa Barbara-Montecito area is small 

compared with the pumpage for municipal use. Pumping of this type 

has declined in recent years and by 1964 probably did not exceed about 

200 acre-feet per year in either the Santa Barbara area or in the 

Montecito area.

PERENNIAL YIELD

The term "perennial yield" has many definitions, all of which are 

based on one premise: the long-term dependability of the water supply, 

as expressed by the balance of the items of the ground-water inventory. 

The perennial yield of the ground-water reservoirs in the Santa 

Barbara-Montecito area is the rate at which water can be pumped 

from wells year after year without decreasing ground water in storage 

to the point where the pumping lift would become economically infeasible or where water of poor quality would begin to intrude into the 

reservoir. In this area the intrusion of water of poor quality probably 

would occur first.
GROUND WATER OF SANTA BARBARA-MONTECITO, CALIF. A23

The ground-water storage units of the Santa Barbara-Montecito 

area have a capacity of about 280,000 acre-feet. The ground water can 

be depleted by pumping until one of the above limiting conditions is 

approached. When this occurs, then only as much water can be pumped 

as will be equal to the long-term average inflow to the reservoir 

minus the quantity which must flow to the ocean annually to maintain 

a barrier against sea-water intrusion. This is the perennial yield of the 

aquifer.

The perennial yield for the area of this report cannot be estimated 

with a high degree of accuracy because of a lack of complete data on 

inflow, outflow, and aquifer transmissibilities and because ground 

water within the reservoir is not static, which means that the natural 

inflow-outflow relations of the reservoir system probably will continue to change with time. Pumping ground water from wellr is one 

item that can change these relations. If pumping causes wate1" levels 

to decline, the decline in turn may cause subsurface inflow or influent 

seepage from creeks to increase.

For convenience the perennial yield of the ground-water reservoirs 

in the Santa Barbara-Montecito area can be estimated in two parts. 

One of these reservoirs underlies the area of Santa Barbara (fig. 2, 

storage units 1, 2, and 3), and the other the Montecito area (fig. 2, 

storage units 4 and 5). Each of these reservoirs has a perennial yield 

independent of the other.

An approximation of the perennial yield for the reservoir in the 

area of Santa Barbara can be estimated by referring to the 11-year 

period 1949-59 during which net ground-water storage seems to have 

remained about constant. During that period, inflow was eaual to 

outflow. Thus, the average perennial yield for the area would be 

equal, at least, to the average pumping draft, or about 1,700 acre-feet 

per year. Average annual inflow for the period 1949-59 was estimated 

to be 1,800 acre-feet, as compared with the long-term estimated 

average annual inflow of 2,000 acre-feet per year for the period 1868- 

1964. Also on the basis of these estimates, the ground-water outflow 

to the ocean required to prevent sea-water intrusion seemr to be 

about 100-300 acre-feet per year. Because there is no evidence of 

sea-water intrusion into the area during the period 1949-59, the 

long-term perennial yield for the Santa Barbara area probably is 

more than 1,700 acre-feet per year but less than 2,000 acre-feet 

per year.

A summary of the inflow-outflow relations in the Santa Parbara 

and Montecito areas for the periods 1868-1964, 1949-59, and 1944- 

64 are summarized in the following table.
A24 CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES

Ground-water inventory for Santa Barbara and Montecito 

[All values rounded]

Average (acre-ft per year)

1868-1964

Santa 

Barbara

Montecito

1949-59

Santa 

Barbara

Montecito

1944-64

Santa 

Ba~bara

Montecito

Inflow

Infiltration of rain (p. A 18) -

Seepage from streams

(p. A20). ___.__ .._

Subsurface inflow from

consolidated rocks

(p. A20)______________

Infiltration of irrigation

Total _ _ ___ ___

1, 100

i 500

300

100

2,000

1,800

i 500

300

100

2,700

1,000

400

300

100

1,800

1,600

400

300

100

2,400

700

400

300

100

1,500

1, 20C

400

300

100

2, 000

Outflow

Pumpage: 

Municipal (p. A22)__ 

Other (p. A22)______

Subsurface discharge to

Total_____ _______

100-300

n

100-300

«

1,500 

200

100-300

1, 800-2, 000

100

200

100-300

400-600

100-300

(3)

100-300

m

1 Estimated from long-term rainfall-runoff relation.

2 No records prior to 1947.

3 No estimate possible.

The perennial yield of the Montecito area is not determinable 

with data now available. Only small-scale development of ground 

water has occurred within the area and apparently has not altered 

appreciably the natural inflow and outflow. Theoretically, the perennial yield of the Montecito area equals the average long-term inflow, 

which is about 2,700 acre-feet per year, minus the outflow that is 

required to maintain ground-water levels high enough to prevent 

sea-water intrusion. If the quantity of outflow required to prevent 

sea-water intrusion is about equal to the quantity of outflow from 

the Santa Barbara area (about 100-300 acre-ft per year), the perennial 

yield of the Montecito area may be approximately 2,500 acre-feet 

per year.

If, during any period, pumpage equals perennial yield and inflow 

is less than the long-term average, ground water in storage will
GROUND WATER OF SANTA BARBARA-MONTECITO, CALIF. A25

decline. This occurred in the Santa Barbara area during the brought 

years 1944-64 when inflow averaged only about 1,500 acre-feet per 

year.

To obtain the full perennial yield from the Santa Barbara-Montecito 

area, careful placement of wells and proper pumping techniques will 

be required. Also, estimates of perennial yield are always subject to 

refinement as additional information becomes available during use of 

the reservoir system.

CHEMICAL QUALITY

The source of most potable ground water is rain. Most dissolved 

mineral matter in streams and ground water is added to the rain after 

it has reached the land surface and begins to run over or percolate 

through the rock materials which mantle the earth. As it moves, the 

ground water dissolves a small quantity of all material with yhich it 

comes in contact. This dissolved material is carried along with the 

water in a number of physical and chemical forms. The value of a 

water supply depends, in part, upon the character and quantity of 

this dissolved-mineral matter and the use for which the water is 

intended.

Most ground water in the Santa Barbara-Montecito area is of 

suitable quality for ordinary domestic and industrial uses. Notable 

exceptions are ground water in some of the consolidated rocks of 

Tertiary age and water from, several wells adjacent to ihe ocean. 

Water from those sources has a total dissolved-solids content of 

1,000-17,500 ppm (parts per million) and is too saline for most needs 

in the area.

Some water in the deeper parts of the ground-water basin in the 

Santa Barbara area presumably is of poor quality. This is suggested 

by the electric log from well 4N/27W-16E1 (pi. 2), which records 

a large negative departure on the self-potential curve anc1 a low 

resistivity through the interval 490-570 feet below sea level. On 

an electric log this combination generally indicates saline water.

Most of the ground water pumped in the area is used for domestic 

purposes. According to the drinking-water standards of the U.S. 

Public Health Service (1962), which are commonly used to evaluate 

domestic water supplies used on interstate carriers, dissolved solids 

should not exceed 500 ppm. However, if water of this quality is not 

available, a dissolved-solids content of 1,000 ppm is permitted.

The following table lists the approximate concentrations of nitrate 

(NO3), sulfate (SO4), and chloride (01) in samples of ground water 

from the area, and the limits recommended by the U.S. Public Health 

Service (1962). These particular ions were chosen for inclusion in the 

table because they serve as an index of the quality of the ground 

water.
A26 CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES

Area

Montecito __ ____

Recommended limit_____

Nitrate

<10

<25

45

Parts per million

Sulfate

100-150

150-250

250

C'lloride

<100

150

250

The range in total dissolved solids in ground-water samples for the 

Santa Barbara area is about 450-650 ppm and for the Mortecito area 

about 600-1,000 ppm. Although the water is, in general, of good 

quality, hardness is objectionably high in both areas. It ranges from 

250 to 500 ppm. Hem (1959, p. 147) stated that hardness of a domestic 

water supply does not become objectionable until it reaches about 100 

ppm. Hardness is undesirable in domestic water supplies because of 

its scale-forming and soap-consuming properties which are caused by 

carbonate and bicarbonate salts, principally magnesium and calcium.

Ground water from some wells near the Mesa fault (pi. 1) contains 

dissolved hydrogen sulfide gas. This gas probably originates in the 

underlying consolidated rocks of Tertiary age and moves upward 

toward the surface along the fault. There has been no pumping of 

ground water near the Mesa fault for many years.

SEA-WATER INTRUSION

Where there is heavy pumping from wells along the coast, the 

possibility of sea-water intrusion must always be considered as a 

potential source of contamination to aquifers in the area. The intrusion of sea water into coastal aquifers can occur in two ways: by 

horizontal migration into the aquifer at depth or by lateral movement 

through shallow deposits adjacent to the ocean with subsequent 

downward migration. Either way, the water level or head of water 

in an aquifer at the coast, in relation to sea level, is the controlling 

factor that determines if sea water intrusion will occur. If groundwater levels in the reservoir system adjacent to the coast are near 

or below sea level, sea-water intrusion is likely to occur.

Static ground-water levels near the coast in the area of Santa 

Barbara and the western part of the Montecito area have b^en below 

sea level since 1960. Sea water apparently has intruded as the water 

level has declined. The intrusion is not extensive and seems to be 

limited to the shallow deposits directly adjacent to the coast. Only wells 

less than 50 feet deep and deep wells which have been constructed without sealing off the near-surface water-bearing zones have been affected. 

Water from observation well 4N/27W-22A1 (pi. 1), which is 31 feet 

deep, had a chloride concentration of 17,500 ppm in 1962. In contrast,
GROUND WATER OF SANTA BARBARA-MONTECITO, CALIF. A27

SOUTH

Sea water moving laterally 

and downward

NORTH

- 100'

Casitas and Santa Barbara Formations

SEA LEVEL

1 MILE

FIGURE 4. Geology and direction of movement of sea water into the groundwater reservoir in the vicinity of sec. 19, T. 4 N., R. 26 W.

water from well 4N/27W-24D2 (pi. 1), which was complete! to a 

depth of 473 feet and sealed from the shallow aquifers with cement 

between the surface and a depth of 116 feet, had a chloride concentration of about 200 ppm in 1962. Water from well 4N/26W-19D2 (pi. 1), 

which is 487 feet deep, had a chloride concentration of about 2,000 

ppm in 1964; when this well was drilled no cement seal was provided 

through the shallow aquifers.

The rather limited data that are available suggest that no direct 

horizontal migration of sea water has occurred at depth into the main 

aquifers. The possibility that horizontal migration could occur seems 

remote because there is no direct connection between the deeper 

water-bearing zones and the ocean. Consolidated rocks of Tertiary 

age have been uplifted on the south side of an offshore fault (pis, 1 and 

2), and these serve as an effective salt-water barrier.

The sketch shown in figure 4 illustrates the near-shore geologic 

conditions in the vicinity of sec. 19, T. 4 N., R. 26 W., and the probable 

direction of movement of sea water into the ground-water reservoir.

CONCLUSIONS

1. The unconsolidated deposits of Quaternary age (alluvium, Casitas 

Formation, and Santa Barbara Formation) make up the groundwater reservoirs in the Santa Barbara-Montecito area.
A28 CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES

2. In 1959 ground water in storage in the Santa Barbara area was 

about 184,000 acre-feet. By 1964, in response to beT ow-average 

recharge and continued withdrawal, the quantity of ground 

water in storage had decreased to about 178,000 acre-feet, the 

lowest on record.

3. In 1959 ground water in storage in the Montecito arer, was about 

97,000 acre-feet. Water levels indicate little change in the quantity of ground water in storage from 1959 to 1964.

4. For the ground-water reservoir in the Santa Barbara area, the calculated perennial yield is between 1,700 and 2,000 acre-feet per 

year.

5. Data are insufficient to make a firm estimate of perennial yield for 

the Montecito area. However, the long-term perennial yield 

may be about 2,500 acre-feet per year.

6. Most ground water in the area is suitable for ordinar^ domestic 

and industrial uses.

7. Locally, sea-water intrusion has occurred as ground-vater levels 

declined below sea level adjacent to the coast. The intrusion is 

limited to the upper parts of near-shore shallow alluvial deposits. 

Ocean water has contaminated only those deep wells which were 

constructed without a cemented seal between the casing and

shallow aquifers.

REFERENCES

Blaney, H. R., 1933, Rainfall penetration, in Ventura County investigation :

California Dept. Public Works, Div. Water Resources Bull. 46, p. 82-91. 

Evenson, R. E., Wilson, H. D., Jr., and Muir, K. S., 1962, Yield of the Carpinteria and Goleta ground-water basins, Santa Barbara County, California,

1941-58: U.S. Geol. Survey open-file rept., 112 p. 

Hem, J. D., 1959, Study and interpretation of the chemical characteristics of

natural water: U.S. Geol. Survey Water-Supply Paper 1473, 269 p. 

Meinzer, O. E., 1923, Outline of ground-water hydrology, witl definitions:

U.S. Geol. Survey Water-Supply Paper 494, 71 p. 

State of California, Department of Natural Resources, Division of Mines, 1954,

Geology of southern California: Bull. 170, map sheet 25. 

Troxell, H. C., and others, 1942, Floods of March 1938 in southern California:

U.S. Geol. Survey Water-Supply Paper 844, 399 p. 

Upson, J. E., 1951, Geology and ground-water resources of the south-coast

basins of Santa Barbara County, California, with a section on Purface-water

resources, by H. G. Thomasson, Jr.: U.S. Geol. Survey Water-^ ipply Paper

1108, 144 p. 

U.S. Public Health Service, 1962, Public Health Service drinking water standards,

1962: U.S. Public Health Service Pub. 956, 61 p. 

Woodring, W. P., Stewart, Ralph, and Richards, R. W., 1940, Geology of the

Kettleman Hills oil field, California; stratigraphy, paleontology, and structure: U.S. Geol. Survey Prof. Paper 195, 170 p.
UNITED STATES DEPARTMENT OF THE INTERIOR 

GEOLOGICAL SURVEY

R. 28 W. R. 27 W 119°45

PREPARED IN COOPERATION WITH THE 

SANTA BARBARA COUNTY WATER AGENCY

40' R. 27 W R. 26 W.

WATER-SUPPLY PAPER 1859-A 

PLATE 1

119°35'

34°30'

EXPLANATION

UNCONSOLIDATED DEPOSITS

Contact, approximately located 

U

Fault

Dashed where inferred or concealed; queried where 

doubtful. U, upthrown side; D, downthrown side

Boulders, cobbles, gravel, sand, silt and clay; permeable; yields water to wells; includes younger alluvium, terrace deposits, and older alluvium, undifLine of geologic section 

Sections shown on plate

,80

Strike and dip of beds

75

Boulders, cobbles, gravel, sand, silt, and clay; permeable; yields water to wells in the montecito area

Strike and dip of overturned beds

Dl

Santa Barbara 

Area of this report' ^\»Los Angeles

Water well and number 

Rl

Santa Barbara Formation

Gravel, sand, silt, and clay; marine; fossiliferous; 

permeable; yields water to wells

Dry or destroyed water well and number

CONSOLIDATED ROCKS

Sedimentary rocks

Sandstone, siltstone, mudstone, and shale; include

Monterey Shale, Rincon Shale, Vaqueros Sandstone,

Sespe Formation, and Tejon Formation; yield water

to wells from fractures and sandstone units

34°22'30

119°45; 42'30" 40' 37'30"

Base from U.S. Geological Survey Goleta, 1950, 

Santa Barbara, 1952, and Carpinteria, 1952

119*35'

INTERIOR GEOLOGICAL SURVEY, WASHINGTON, D.C. 1968 VV6731O

Geology by K. S. Muir modified from Upson (1951, 

pis. 1,2) and Dibblee, unpublished geologic 

map of the central Santa Ynez mountains 

and vicinity. Surveyed in 1963-64

34°22'30"

MAP SHOWING MAJOR GEOLOGIC FEATURES AND LOCATION OF WATER WELLS 

SANTA BARBARA-MONTECITO AREA, SANTA BARBARA COUNTY, CALIFORNIA

SCALE 1:24000

0 1 MILE

.5 1 KILOMETER

CONTOUR INTERVALS 20 AND 50 FEET 

DATUM IS MEAN SEA LEVEL
UNITED STATES DEPARTMENT OF THE INTERIOR 

GEOLOGICAL SURVEY

PREPARED IN COOPERATION WITH THE 

SANTA BARBARA COUNTY WATER AGENCY

WATER-SUPPLY PAPER 1859-A 

PLATE 2

SEA LEVEL

EXPLANATION

TRACE OF SECTIONS SHOWN 

PLATE 1

LITHOLOGIC UNITS

Boulders and cobbles

Sand

Clay and gravel

Gravel

Sand and gravel

Sandy clay

400' -,

300' -

2o°; ~!

100' -

SEA LEVEL Silt and clay Shale

Fossil shells

SELF-POTENTIAL RESISTIVITY

900' 900'

GEOLOGIC SECTION A-A' ACROSS THE CITY OF SANTA BARBARA

Fault, approximately 

located

Queried where doubtful. Arrows 

indicate relative direction of 

movement

SEA LEVEL

100' -

200' -

300' -

400' -

500' -

600' -

700' -

800' -

900

Casitas and Santa 

Barbara Formations

SEA LEVEL

900'

B-B' ACROSS THE MONTECITO AREA

GEOLOGIC SECTIONS OF THE SANTA BARBARA-MONTECITO AREA, SANTA BARBARA COUNTY, CALIFORNIA

SCALE 1:24000

0

i i________

1 MILE

I

.5 1 KILOMETER

VERTICAL EXAGGERATION X 10

288-767 O - 68 (In pocket)