2 11Resource Description

Photos (clockwise): 1. Equestrian, San Gabriel River. NPS Photo. 2. Hiking, Puente Hills. NPS Photo. 3. Santa Fe Dam Recreation

Area. NPS Photo. 4. Dried grasses and chaparral on a ridge in the San Gabriel Mountains. Photo © Gary Ferguson.
12 Draft San Gabriel Watershed and Mountains Special Resource Study & Environmental Assessment 
Chapter 2: Resource Description Natural Resources 13

Chapter 2: Resource 

Description

Natural Resources

Climate

The Los Angeles region has a Mediterranean type 

climate associated with areas located between the 

30th and 45th parallels of latitude and on western 

continental borders (Bailey 1966). These areas are 

affected by subtropical high pressure masses that 

create a drought environment during summer, but 

shrink in winter, allowing storms to enter along 

the coast. Only two percent of the earth’s surface 

has this type of climate. Other locations with this 

climate include areas in southern Europe and North 

Africa on the Mediterranean Sea, Chile, South 

Africa, and Australia. The climate is highly affected 

by marine infl uences. Marine air keeps the coast 

cool in the summer and prevents it from getting 

very cold in the winter (Miller and Hyslop 1983).

At times, offshore winds from the east infl uence 

the climate. Between September and March, a high 

pressure system over the Great Basin, combined 

with a low pressure system to the southwest, 

creates warm, dry winds that circulate through 

the region. Known as the Santa Ana winds, these 

winds have a signifi cant impact on the local climate. 

After the long dry summers, the Santa Ana winds 

contribute to the fi re regime, which begins in the 

summer season and continues until the wet winter 

ensues. 

The mountains and coastal ranges block the moist 

sea air, creating an arid, desert climate north of 

the San Gabriel Mountains. Since the mountain 

ranges and hills completely surround the valleys, 

temperature inversions create conditions where 

smog stays in the environment. The mountains 

and hills further this condition by preventing 

horizontal air movements. The San Gabriel Valley, 

with mountains to the north and hills to the south, 

is particularly impacted by smog (Miller and Hyslop 

1983). 

MICROCLIMATES

Although the Los Angeles region is known for its 

year-round mild climate, there are many different 

microclimates in the valleys, mountains, hills, and 

coastal areas of the study area. Average rainfall 

and temperature varies signifi cantly throughout 

the study area based on the local microclimate. For 

example, average annual precipitation is 32.9 inches 

for the San Gabriel Mountains, 15.5 inches for the 

Los Angeles basin, and 7.8 inches for the Antelope 

Valley (LADPW 2006c). Within the study area, there 

are seven defi ned microclimates.

Semi-marine Climatic Zone

Areas south of the Puente-Chino Hills are under the 

infl uences of sea breezes from the coast. Frost is 

rare and summers are mild. 

Air Drainage Thermal Climatic Zone

The Puente-Chino Hills are in this climate zone 

where summer temperatures are warmer than in 

the semi-marine climate zone. The topography of 

the hills drains cold air on winter nights, protecting 

this area from frost. 

Valley Margin Climate

The high ground at the base of the surrounding hills 

and mountains of the San Gabriel Valley are located 

far enough from the ocean that they experience hot 

summer days while nights remain relatively cool. 

Valley Floor Climate

On the San Gabriel Valley fl oor, summer days are 

hot and sunny and nights are relatively cool. In 

winter, the valley fl oor is subject to frost as cool air 

tends to collect on the valley fl oors. 

Transitional Mountain Climate

The southern face of the San Gabriel Mountains is 

a transition zone between the valley margins and 

alpine climates. As elevation increases, precipitation 

increases and temperatures decrease.

Alpine Climate

Above 4,000 feet, the alpine environment is 

characterized by distinct seasonal differences in 

temperature and features the highest precipitation 

in the region. Winters are very cold and summer 

temperatures are still relatively high.

High Desert

At the northern base of the San Gabriel Mountains, 

the high desert climate of the Antelope Valley is 

characterized by less than ten inches of rainfall a 

year. Summers are extremely hot and winters are 

unusually cold (Miller and Hyslop 1983).
14 Draft San Gabriel Watershed and Mountains Special Resource Study & Environmental Assessment 

Topography

SAN GABRIEL MOUNTAINS

The San Gabriel Mountains are part of the 

Transverse Ranges geomorphic province which 

includes geologic structures along the southern 

California coastline that lie east-west or “transverse 

to” the prevailing northwest-trending character of 

the west coast. Additional mountain ranges within 

the Transverse Range province include the Santa 

Ynez Mountains, the Santa Monica Mountains, 

and the San Bernardino Mountains. The northern 

extent of the study area follows the San Andreas 

fault, which also serves as the boundary between 

the Transverse Ranges and the Mojave Desert 

geomorphic province (See Map: Topography).

The San Gabriel Mountains are about 50 miles 

long and 15 miles wide. With the exception of a 

small portion in San Bernardino County, most of 

the mountain range is within the study area. The 

San Gabriel Mountains are some of the highest and 

most rugged of all the mountains in the Transverse 

Ranges. The highest peak, located in the eastern 

portion of the mountains, is Mt. San Antonio. Also 

known as “Mt. Baldy” or “Old Baldy,” this peak 

reaches a height of 10,064 feet. Mountains on the 

western end of the range are lower in elevation, 

around 4,000 to 6,000 feet in height. 

The steep, high relief of the San Gabriel Mountains 

forms the dramatic mountainous backdrop of the 

Los Angeles basin. The San Gabriel Mountains rise 

quickly from the foothills; slopes are as steep as 

65-70%. This can be attributed to the fact that the 

San Gabriel Mountains are a young mountain range 

growing at a rapid rate. They are considered one of 

the fastest growing mountain ranges in the world, 

rising as much as 2 inches per year (LADPW 2006b).

The San Gabriel Mountains and San Bernardino 

Mountains form the divide between the Pacifi c 

Ocean drainage area and rivers that drain to the 

Mojave Desert. Most of the mountains drain to the 

Pacifi c Ocean through the Santa Clara, Los Angeles, 

San Gabriel, and Santa Ana Rivers. The northeastern 

areas drain to the Mojave Desert. 

LOS ANGELES BASIN

The mountains of the Transverse and Peninsular 

Ranges surround the Los Angeles basin, the 

low area that stretches south of the San Gabriel 

Mountains to the coast. The Los Angeles basin 

is a large fl ood plain and alluvial fan which lies 

at the northern extent of the Peninsular Ranges 

geomorphic province. The Puente-Chino Hills 

form an east-west chain that cuts through the Los 

Angeles basin extending from the Chino Hills west 

to Elysian Park in Los Angeles. This range separates 

the San Gabriel Valley and from the southern 

coastal plain of the basin that stretches west to the 

Pacifi c Ocean. Within the study area, the PuenteChino Hills reach 1,388 feet at Workman Hill north 

of Whittier. The San Jose Hills, which lie north of 

the Puente-Chino Hills, are a smaller range that 

trends southwest. Buzzard Peak (1375 feet) is the 

highpoint of the San Jose Hills. Whittier Narrows is 

a natural gap between the Puente and Montebello 

Hills where the San Gabriel and Rio Hondo Rivers 

converge.

SOLEDAD BASIN/ SANTA CLARITA VALLEY

The Soledad basin lies at the northwestern base 

of the San Gabriel Mountains. On the north it 

is defi ned by the Sierra Pelona Range. The San 

Andreas fault and the San Gabriel fault bound the 

basin on its northeast and southwest borders. The 

upper Santa Clara River and its headwaters drain 

from both the San Gabriel Mountains and the Sierra 

Pelona Range into the Soledad basin and Santa 

Clarita Valley. 

ANTELOPE VALLEY/MOJAVE DESERT

North of the San Gabriel Mountains lies the 

Antelope Valley, high desert terrain in the 

southernmost extent of the Mojave Desert. The 

Antelope Valley is comprised of a great alluvial fan 

which has been created by years of deposition from 

rivers in the San Gabriel Mountains. This area’s 

topography is also characterized by the San Andreas 

rift zone which includes a series of northwesttrending trough-like valleys and bordered by linear 

ridges (Mattison and Barrows 2003). The California 

Aqueduct traverses the northernmost point of 

the study area where it crosses through the San 

Andreas rift zone.

South of the fault lies Lake Palmdale, a natural sag 

pond that was later modifi ed to serve as a reservoir 

(Mattison and Barrows 2003). Big Rock, Little Rock, 

and Mescal creeks drain from the San Gabriel 

Mountains into the Antelope Valley and the Mojave 

Desert. 

Geologic Resources

The assemblage of rocks in the study area is quite 

diverse with the San Gabriel Mountains featuring 

some of the oldest rocks in California. The region is 

experiencing active mountain-building and the San 

Gabriel Mountains are some of the fastest growing 

mountains in the world. This is contrasted with the 

Los Angeles basin which consists primarily of recent 

alluvium deposited across the basin by the series of 
Chapter 2: Resource Description Natural Resources 15
16 Draft San Gabriel Watershed and Mountains Special Resource Study & Environmental Assessment 

rivers that run from the San Gabriel Mountains to 

the Pacifi c Ocean. This alluvium, which is thousands 

of feet deep in many locations, is a repository for 

petroleum resources. Hill formations on the Los 

Angeles basin are also relatively young and rich in 

petroleum. 

The following section describes the geologic 

history of the region, rock formations, faults, and 

modern geological processes such as erosion, 

landslides, and earthquakes.

GEOLOGIC HISTORY

The geologic history of the San Gabriel Mountains 

and the Los Angeles basin involves vertical and 

lateral movements of great magnitude. The San 

Gabriel Mountains are a remarkable range that 

provides a window deep into the ancient crust of 

the earth and a key for understanding the evolution 

of the San Andreas fault in southern California. 

These movements are largely a result of plate 

tectonics. The San Andreas fault is the location 

where the Pacifi c Plate meets the North American 

Plate, also known as a transform plate boundary. 

When these plates collide or converge, they create 

geologic phenomena such as earthquakes, volcanic 

eruptions, and tsunamis. In addition to plate 

tectonics, the region has experienced geological 

changes from erosion, deposition, and volcanic 

activity (USGS 2006).

The following section provides an overview of the 

area’s geologic history according to eras of the 

geologic time scale developed by the Geological 

Society of America. 

Precambrian History 

(3800 – 543 million years ago)

The oldest rocks in California are associated with 

the early to middle eras of the Proterozoic age 

(2500 to 543 million years ago). These ancient 

rocks have been thrust to the surface areas of 

the San Gabriel Mountains by great periods of 

mountain-building. Although these rocks are not 

as old as the 3.6 billion-year old Archean rocks of 

the Lake Superior region, they do form part of the 

Precambrian craton generally found in the core of 

the North American continent (Norris and Webb 

1990, Oakeshott 1971, Schoenherr 1992).

Paleozoic History (543-248 million years 

ago)

During the Paleozoic era, the Mojave region formed 

the continental margin. The lands that would one 

day form the San Gabriel Mountains and the Los 

Angeles basin were covered by the ocean. During 

this time, the sea level fl uctuated across the Mojave 

region. Evidence of marine life is preserved in rocks 

of the eastern Mojave Desert (USGS 2006).

Mesozoic History (248-65 million years 

ago)

The great mountain systems of California began 

to form during the Mesozoic era when the Pacifi c 

Plate dove under the North American Plate, a 

process known as subduction. This rising caused a 

spreading of the Pacifi c Ocean fl oor which, in turn, 

pushed the Pacifi c Plate into the North American 

plate. This action also formed a series of volcanoes 

along the continental margin. The magma that 

intruded into the North American plate formed 

what is known as a batholith (a deep rock mass). 

This batholith forms the base of the southern Sierra 

Nevada, the Mojave region, and portions of the 

Peninsular Ranges (Schoenherr 1992). 

Cenozoic History 

(65 million years ago to present)

The Cenozoic era brought long periods of 

erosion and sedimentation and the evolution of 

the San Andreas transform fault system. During 

the early Tertiary period (65 million years ago to 

approximately 1.8 million years ago), subduction 

of the Pacifi c Plate under the North American 

Plate continued and the southern California region 

experienced great uplifts and erosion.

Paleogene-Neogene Epochs (65 to 23 million 

years ago). During this early period of the 

Cenozoic era, the San Gabriel Mountains and Los 

Angeles basin lie beneath swampy sea-marshes 

and lagoons receiving sediment from the ancestral 

Nevadan mountains (Los Angeles Almanac 2005). 

Paleocene-Eocene-Oligocene Epochs (34 to 24 

million years ago). Uplift and erosion during this 

time period formed a landscape of rolling lowlands 

with a few mountains. West of the mountains 

were shallow embayments. Rivers and streams 

carried down sediments from the mountains 

depositing them on the continental margin and in 

offshore basins. 

Micocene Epoch. During the early Miocene 

epoch, (24 to 5 million years ago) modern coastal 

California began to emerge. Seas spread more and 

more widely over the western Transverse Ranges 

and a deep trough developed in the Los Angeles 

basin and Channel Islands. About 16 million years 

ago, the San Gabriel Mountains began to elevate 

(McCulloh, Beyer, and Morin 2001; Oakeshott 

1971; Schoenherr 1992).
Chapter 2: Resource Description Natural Resources 17

The middle Miocene was a time of great volcanism 

in the Transverse Ranges. Some of the thickest 

rocks are associated with this epoch. The Glendora 

volcanics occur along the southern front of 

the San Gabriel Mountains (Oakeshott 1971). 

Paleomagnetic data in the volcanic rocks of this age 

found in the San Gabriel Mountains, Santa Monica 

Mountains, and Channel islands indicate that 

these features rotated about 90 degrees clockwise 

(Schoenherr 1992). This rotation, caused by the 

collision of the North American and Pacifi c plates, 

began about 20 million years ago.

Pliocene Epoch. During the Pliocene epoch (5 - 1.8 

million years ago), the Los Angeles basin subsided 

at an accelerated rate. As the Los Angeles basin 

continued sinking, sediments were deposited in 

as much as 6,000 feet of water. By the end of the 

epoch, more than 10,000 feet of sediment were 

deposited in the basin (Norris and Webb 1990). 

Pleistocene Epoch. In the early Pleistocene epoch 

(1.8 million - 8,000 years ago), the central Los 

Angeles basin continued to receive marine deposits 

as high sea-levels and inland bays covered the 

coastal plains and lowlands of southern California 

(Norris and Webb 1990). 

By the middle Pleistocene the shoreline of the basin 

sea probably extended to the southern margin of 

the Santa Monica chain and along the Whittier fault 

zone (Norris and Webb 1990). This period also saw 

sea level rises associated with the melting of polar 

ice caps from an ice age that occurred 20,000 years 

ago, fl ooding the Los Angeles basin (Schoenherr 

1992). The Los Angeles basin experienced more 

subsidence. However, the surrounding mountain 

ranges underwent considerable uplift. Dramatic 

uplifting continues in the region today (Norris and 

Webb 1990). The rapid uplift of the mountains 

caused erosion and created the dramatically steep 

slopes of the San Gabriel Mountains. 

The thick marine sediments of the Los Angeles 

basin that were deposited during the Pliocene and 

Pleistocene epochs formed vast deposits of fossil 

fuels. The Los Angeles basin is California’s most 

prolifi c oil producing district in proportion to its size 

(Yerkes, McCulloh, Schoellhamer and Vedder 1965; 

Norris and Webb 1990).

The modern rivers of the region also developed 

during the Pleistocene epoch. Major rivers of the 

Los Angeles basin predate the Puente-Chino and 

Repetto Hills. These hills are so young, geologically 

speaking, that they literally formed around the 

rivers. This is evident in the series of gaps found in 

the Los Angeles basin hill systems. Whittier Narrows 

is an excellent example of this kind of water gap. 

As the young Puente-Chino Hills began to rise, 

the smaller creeks in the basin which had drained 

to the ocean changed course and some became 

tributaries of the San Gabriel River. Because of the 

force of the San Gabriel River channel itself, the 

hills rose around the river forming Whittier Narrows 

(Sharp 1975). By the end of this time, the shoreline 

recedes to approximately where it is today.

Holocene Epoch. (8,000 years ago to present. 

Uplift of the mountains and deposition of alluvium 

continues to shape the landscape (USGS 2006).

ROCK FORMATIONS

Rock formations in the study area, particularly in 

the San Gabriel Mountains, are quite diverse in age 

and composition. The following section highlights 

some of the major geologic formations and features 

of the study area.

The San Gabriel Mountains rock formations range 

from Precambrian igneous and metamorphic rocks 

to recent alluvium deposited by streams and rivers 

(see Map: Generalized Geology). Bedrock units in 

the San Gabriel Mountains are comprised primarily 

of crystalline basement rocks which range in age 

from the Precambrian to Mesozoic eras. Cenozoic 

beds are located only along the range’s margins. 

A signifi cant geologic structure, the Vincent thrust, 

separates two distinct sets of crystalline basement 

rocks in the San Gabriel Mountains. During the 

Mt. Lowe Pluton Unit with monzogranite or mylonitic 

dike. NPS photo.
18 Draft San Gabriel Watershed and Mountains Special Resource Study & Environmental Assessment 
Chapter 2: Resource Description 

Natural Resources 19

late Cretaceous period (99 to 65 million years ago), 

the Vincent thrust fault brought upper and lowerplate masses together. This occurred on a regional 

scale; however, the event is best-exposed and most 

evident in the San Gabriel Mountains. Basement 

rocks of the Western San Gabriel Mountains consist 

primarily of rocks associated with the upper plate 

of the Vincent thrust while the eastern San Gabriel 

Mountains basement rocks are associated with the 

lower plate. Intruded throughout the San Gabriel 

Mountains are Mesozoic granitic rocks which make 

up nearly half of the range’s basement rocks. Gneiss 

is the most widespread metamorphic rock in the 

San Gabriel Mountains (Ehlig 1982). 

Western San Gabriel Mountains (including 

Soledad Basin)

Basement rocks exposed in the western San Gabriel 

Mountains, the upper-plate rocks of the Vincent 

thrust, include Mendenhall gneiss, augen gneiss, 

and the anorthosite-syenite-gabbro complex. 

Augen gneiss in the western San Gabriel Mountains 

have been dated as the oldest rocks in the 

Transverse Ranges (1.7 billion years). Triassic granitic 

rocks associated with the Mount Lowe plutonic 

suite are also exposed here (Dibblee 1982; Norris 

and Webb 1990). The anorthosite complex includes 

an anorthosite pluton, syenite, and mafi c rocks of 

a Proterozoic age. This complex is rare, particularly 

in a relatively young geological landscape (Dibblee 

1982). 

Soledad basin contains various tertiary rock units. 

The marine Martinez formation of Paleocene age 

is the oldest sedimentary unit in the region. This 

formation is overlaid by the Oligocene Vasquez 

formation of andesite volcanic rocks, nonmarine red beds, sedimentary breccia, claystone, 

mudstone, and limestone. The Vasquez formation 

is spectacularly displayed at Vasquez Rocks County 

Park just north of the study area (Weigand 1982).

Overlaying the Vasquez formation is the Miocene 

Tick Canyon formation, which is comprised of 

conglomerate sandstone and siltstone of fl uvial 

origin (Oakeshott1971).

The most widespread formation in the 

Soledad basin is the Mint Canyon formation. 

These distinctive reddish beds of arkosic and 

conglomerate sandstone formed from silt deposits 

in an ancient Miocene lake. A considerable number 

of fossils have been identifi ed in the Mint Canyon 

formation. The Miocene Castaic formation contains 

shallow marine sandstone and shale. This formation 

is distinctive as it contains about 100 species 

of fossils, mostly mollusks that are commonly 

associated with the Miocene epoch (Stanton 1966). 

Geology Legend
20 Draft San Gabriel Watershed and Mountains Special Resource Study & Environmental Assessment 

Photos (top to bottom): 1. Glendora Volcanics, Central 

San Gabriel Mtns 2. Augen gneiss boulder, Western 

San Gabriel Mnts 3. Anorthosite, Angeles Crest 

Highway, Western San Gabriel Mnts . NPS Photos.

Younger tertiary formations include the Pliocene 

Towsley formation, which consists of interbedded 

marine siltstone, mudstone and conglomerate, 

and the non-marine Plio-Pleistocene Saugus 

formation, which contains arkosic sandstone, 

sandy conglomerate, and siltstone. The Pleistocene 

Pacoima formation contains non-marine silty 

sandstone and pebble boulder conglomerate 

(Wilson and Haydon 1998). 

In the southwest corner of the mountains, the 

Tujunga Terrane, named for rocks exposed in lower 

Tujunga Canyon, contains basement rocks such 

as gneisses, late quartz diorite, and granodioritequartz, as well as metasedimentary rocks associated 

with the pre-Triassic Placerita formation.

Central San Gabriel Mountains

A main feature of the central San Gabriel 

Mountains is the Triassic Mount Lowe plutonic suite 

(also known as Lowe Granodiorite or the Lowe 

Igneous Pluton). This large pluton extends from 

upper Soledad basin to Little Rock Canyon. Isolated 

remnants are also found near Crystal Lake (Dibblee 

1982). The Mount Lowe plutonic suite consists of 

four zones that include hornblende, potassium 

feldspar, garnet, and biotite (Joseph, Criscione, 

Davis, and Ehlig 1982).

A diversity of rock types occur along the active 

San Andreas fault zone. In the Little Rock Creek 

area, the non-marine Pliocene-Miocene Anaverde 

formation is exposed in terrain between the Little 

Rock fault and the San Andreas fault. The oldest 

rocks north of the San Andreas fault zone consist of 

Holcomb quartz monzonite that is exposed in the 

ridges of Little Rock fault and along the California 

Aqueduct west of Little Rock Wash. 

Quaternary formations along the San Andreas fault 

zone include the Juniper Hills formation, crushed 

pebbly sandstone, and the Harold formation with 

its fi ne-grained, silty to sandy, moderately wellstratifi ed fl uvial, alluvial fan, and playa deposits.

Eastern San Gabriel Mountains

Most of the northeastern San Gabriel Mountains 

are characterized by lower plate rocks of the 

Vincent thrust. These include the Paleozoic or 

Mesozoic metamorphosed sedimentary and 

volcanic rocks known as Pelona schist. Two distinct 

blocks of the Pelona schist are separated by the 

Punchbowl strand of the San Andreas fault, the 

Blue Ridge block, and the Lytle Creek block. Pelona 

schist is overlain by Mylonitic metamorphic rocks 

of the Vincent thrust fault zone. This structure is 

well-exposed in eastern San Gabriel Mountains just 
Chapter 2: Resource Description Natural Resources 21

south of the Punchbowl fault (Morton and Miller 

2003 Dibblee 1982). 

Between the Punchbowl and San Andreas faults 

are the tertiary Punchbowl and San Francisquito 

formations. The San Francisquito formation 

consists of marine sedimentary rock of Paleocene 

age. It is composed of shale in its upper part 

and sandstone in its lower part (Dibblee 1982). 

The lower Pliocene/upper Miocene Punchbowl 

formation, which overlays the San Francisquito 

formation, forms striking exposures known as the 

“Devil’s Punchbowl” (Morton and Miller 2003). The 

scenic Devil’s Punchbowl consists of magnifi cently 

exposed ridges and ravines etched into steeply 

tilted and folded sandstone. Movement along the 

San Andreas and Punchbowl faults down-dropped 

the Devil’s Punchbowl formation into areas of older 

crystalline rocks. 

Basement rocks of the southeastern San Gabriel 

Mountains include Mesozoic quartz diorite and 

monzonite and quartz diorite mylonite (Dibblee 

1982). Also present in this area are Proterozoic 

garnet-pyroxene-bearing quartz, feldspathic gneiss, 

marble and calc-silicate rocks, Mesozoic, and 

Cretaceous granitic rocks.

The Glendora volcanics are exposed in areas 

along the southwestern front of the San Gabriel 

Mountains. Primarily comprised of rhyolite and 

basalt, fl ow rock and volcanic breccia and tuff, 

these volcanic rocks are the only Tertiary rocks 

in the San Gabriel Mountains on the south side 

of the range. The Glendora volcanics have been 

correlated with the El Modeno volcanics exposed 

on the northwest end of the Santa Ana Mountains 

(Weigand 1982). 

Surfi cial alluvium of varying ages can be found 

overlaying basement and subjacent rocks in creek 

beds and valleys throughout the San Gabriel 

Mountains. Broad alluvial fans are prominent along 

the fl anks of the San Gabriel Mountains. Many of 

the foothill communities south of the San Gabriel 

Mountains are located on these alluvial fans. 

Los Angeles Basin

The Los Angeles basin is separated from the San 

Gabriel Mountains by the Sierra Madre fault zone. 

Basement rocks of the Los Angeles basin portion 

of the study area include Glendora volcanics and 

the Miocene Puente formation, both of which 

are exposed in the Puente and San Jose Hills. 

The Puente formation, primarily composed of 

sandstone, siltstone, and shale, is one of the most 

important oil-producing units of the Los Angeles 

basin (Morton and Miller 2003). The Puente 

formation is overlain by the Pliocene-Fernando 

formation, which consists of interbedded fi ne to 

coarse clastic marine strata. 

Most of the Los Angeles basin area consists 

of alluvium, thousands of feet deep in some 

areas, compiled from years of deposits from 

rivers and streams. Petroleum exploration holes 

drilled thousands of feet below the surface have 

uncovered basement rocks beneath the alluvium. 

These basement rocks have been identifi ed as the 

Photos (top to bottom): 1. Pelona schist. Eastern San 

Gabriel Mountains. 2. Devil’s Punch Bowl. Eastern San 

Gabriel Mountains. NPS photos.
22 Draft San Gabriel Watershed and Mountains Special Resource Study & Environmental Assessment 

Puente formation, Mountains Meadows dacite, 

Glendora volcanics, and Topanga volcanics. 

The Oligocene Mountain Meadows dacite consists 

of biotite rhyolite, quartz latite, and dacite porphyry 

dikes and dike-form bodies. Outcrops of the 

Mountain Meadows dacite are exposed at the 

Mountain Meadows Country Club in Pomona. A 

recent investigation of the Oligocene Mountain 

Meadows dacite concluded that a subsurface 

region of the Mountain Meadows dacite in the 

northeastern Los Angeles basin ties together 

the northern Los Angeles basin, the San Gabriel 

Mountains, San Rafael Hills, and the Verdugo 

Mountains (McCulloh, Beyer, and Morin 2001).

MAJOR FAULTS IN THE STUDY AREA

A number of signifi cant fault systems are located 

in the Los Angeles region and in the NPS study 

area (see Map: Regional Faults). The following 

section provides a short description of the study 

area’s major faults. The San Gabriel Mountains 

are bounded by fault systems including the 

San Andreas fault system to the north and the 

Cucamonga-Sierra Madre fault complex to the 

south and southwest. On the east the mountains 

are bound by faults in the San Jacinto fault zone, an 

extension of the San Andreas fault system. The San 

Gabriel fault zone cuts through the heart of San 

Gabriel Mountains and extends northwest through 

the Sierra Pelona mountains. 

Major faults in the Los Angeles Basin portion of 

the study area include the Raymond fault and the 

Whittier-Elsinore fault. 

In addition to these major faults, the region 

contains blind thrust faults. Blind thrust faults are 

shallow-dipping reverse faults which lie below the 

earth’s surface. While many of these faults remain 

unknown, two regional examples are the Elysian 

Park Thrust, which runs underneath downtown 

Los Angeles and the Northridge thrust fault, which 

ruptured in the 1994 Northridge earthquake.

San Andreas Fault System

The San Andreas fault system formed along the 

translational boundary between the North American 

and Pacifi c Plates. As one of the few places on Earth 

where a transform-fault plate-boundary occurs on 

land rather than beneath the sea, the San Andreas 

fault system is one of the most studied structural 

features on the planet. Convergent transform 

movements are responsible for the mountainbuilding activities which continue to form the San 

Gabriel Mountains and other Transverse Ranges. 

Although the rate of movement varies over time, 

geologists believe that the Pacifi c Plate is currently 

moving northwest at a rate of almost 5 centimeters 

per year. 

The unique assemblage of rocks in the San Gabriel 

Mountains has helped geologists determine the 

magnitude and rate of movement along the San 

Andreas fault. The Vincent Thrust has played a 

particularly important role in understanding plate 

tectonics and movement along the San Andreas 

fault. Remnants of the Vincent Thrust fault and the 

associated upper plate and lower plate rocks are 

located in the Orocopia and Chocolate Mountains, 

located 150 miles to the south on the opposite 

side of the San Andreas fault in Riverside and 

Imperial Counties. Correlations between Pelona 

Schist associated with the Vincent thrust and the 

Chocolate and Orocopia Mountain thrusts indicate 

that the central Transverse Ranges have been 

displaced by 100 to 150 miles (estimates vary) of 

movement along the main trace of the San Andreas 

fault. Cross-fault correlations with other distinct 

units such as the San Gabriel anorthosite, the 

Mount Lowe plutonic suite, Precambrian augen 

gneiss, and Cenozoic sedimentary and volcanic 

rocks have further strengthened this analysis (Norris 

and Webb 1990; Ehlig 1982; Nourse 2002).

Restoration of these ancient rock units of the San 

Gabriel Mountains along faults of the San Andreas 

system uniquely constrains overall displacements on 

the faults of the San Andreas system. In addition, 

debris shed from these distinctive rock units as 

they were exhumed and displaced record the 

San Andreas fault, north of the San Gabriel 

Mountains. NPS photo.
Chapter 2: Resource Description Natural Resources 23

The NPS makes no warranty, express or implied, related to the accuracy or content of this map.
24 Draft San Gabriel Watershed and Mountains Special Resource Study & Environmental Assessment 

Table 1: Signifi cant Earthquakes Within or Near the Study Area

Date Magnitude Name, Location, or

Region Affected Loss of Life and Property

1857, Jan. 9 7.9 Great Fort Tejon 

earthquake

1 dead; damage from Monterey to 

San Bernardino County

1899, July 22 6.4 Wrightwood Chimneys knocked down; landslides reported

1933, Mar. 11 6.4 Long Beach 115 dead; $40 million in property damage

1971, Feb. 9 6.6 San Fernando 65 dead; more than 2,000 injured; 

$505 million in losses

1987, Oct. 1 6.0 Whittier Narrows 8 dead; $358 million in property damage to 

10,500 homes and businesses

1994, Jan. 17 6.7 Northridge 57 dead; more than 9,000 injured; about 

$40 billion in property damage

Source: California Geological Survey 2004. 

timing of movement along the faults. This body of 

information continues to grow as geologists learn 

more about the complex San Gabriel Mountains 

geologic units (Powell 1993).

Throughout the year the San Andreas fault 

experiences many small earthquakes as the Pacifi c 

Plate continues its journey north. Large earthquakes 

are also associated with this fault. Activity along 

the San Andreas fault zone has caused some of the 

largest landslides in California. Examples include 

Crystal Lake in the San Gabriel Mountains, Cow 

Canyon, Manker Flats, and Coldwater Canyon 

(USFS 2005).

Several miles north of the study area, the Fort Tejon 

earthquake of 1857 (8.0 magnitude) was one of 

the largest earthquakes experienced in southern 

California. An extensive rupture was accompanied 

by the greatest right-lateral offset yet observed on 

the San Andreas system, 9m /30ft (Norris and Webb 

1990).

The San Gabriel fault is an older strand of the 

San Andreas fault system. Credited with defi ning 

the general east-west trend of Transverse Range 

structure, the San Gabriel fault strikes southeast 

from Frazier Mountain and enters the San Gabriel 

Mountains on the western end. It appears to be 

offset in the San Antonio Canyon by north-south 

trending San Antonio and Stoddard canyon faults, 

with the eastern segment terminating against 

the San Jacinto fault. The San Gabriel fault’s wide 

crush zone has strongly affected topography and 

drainage. For example, the east and west forks of 

the San Gabriel River follow the fault for most of 

their lengths. 

During the last 12 million years, the San Gabriel 

fault is estimated to have undergone about 60 

kilometers/40 miles of right slip movement, which 

is thought to have ceased about 5 million years 

ago. The San Gabriel fault has also experienced 

varying degrees of vertical displacement. Along 

the southwest side of the Ridge Basin, vertical 

displacement is as much as 14,000 feet. The San 

Gabriel fault has experienced only minor activity in 

recent times (Norris and Webb 1990). 

OTHER FAULT SYSTEMS

The Sierra Madre fault zone and its eastern 

counterpart, the Cucamonga fault, are steep, north 

dipping, front-range faults along which most uplift 

of the San Gabriel Mountains has occurred. Activity 

on this fault is very recent (Norris and Webb 1990). 

The San Fernando earthquake of 1971 (6.6 

magnitude) was one of the strongest earthquakes 

experienced in modern times. The earthquake 

caused over $500 million in property damage and 

65 deaths. Although this earthquake was set off 

by the San Fernando fault zone to the west of 

the study area, seismologists have shown that the 

San Fernando earthquake defi ned a north-dipping 

reverse fault that corresponded to the surface 

breaks observed along segments of the Sierra 

Madre fault zone. The San Fernando earthquake 

alone caused a three-foot uplift of the San Gabriel 

Mountains (Norris and Webb 1990).

The Vasquez Creek fault runs along the south 

face of the San Gabriel Mountains between the 

San Gabriel fault and segments of the Sierra Madre 

fault zone near Pasadena. It is estimated that this 

fault has seen as much as 14 kilometers in right 

slip-movement.

Soledad Basin Faults 

Numerous northeast-striking faults cut across the 
Chapter 2: Resource Description Natural Resources 25

sedimentary and basement rocks of the Soledad 

basin including the Lone Tree and Soledad faults 

(Wilson and Hernandez 2003). 

The Soledad fault runs through Soledad basin 

where it brings the crystalline basement rocks of the 

San Gabriel Mountains in contact with tertiary rocks 

to the west. 

Los Angeles Basin Faults

The Raymond fault extends north from the Santa 

Monica Mountains to the Sierra Madre-Cucamonga 

fault zone near Arcadia. This fault produces a 

very obvious south-facing scarp along much of its 

length. Early explorers noted springs all along the 

Raymond fault. 

The Elsinore fault zone is one of the largest in 

southern California. It spans from the mountains 

east of San Diego northwest to the Los Angeles 

basin where it bifurcates into the Chino fault

on the northeast and the Whittier fault on 

the southwest. The Whittier fault runs directly 

underneath the Puente Hills (Norris and Webb 

1992). 

The 1987 Whittier Narrows earthquake (6.0 

magnitude) that struck the southern San Gabriel 

Valley and surrounding communities of southern 

California was caused by slip on a blind thrust 

fault near the northern end of the Whittier fault. It 

has been proposed that the event occurred on an 

extension of the recently recognized Puente Hills 

thrust fault system.

The San Jose fault runs beneath the San jose Hills 

trending northeast to the Sierra Madre-Cucamonga 

fault zone.

LANDSLIDES

Landslides form widespread and important 

physiographic elements in the highly fractured rocks 

of the San Gabriel Mountains. Some of the largest 

landslides in southern California (including Crystal 

Lake) are located in the Angeles National Forest. 

Large landslides are infrequent occurrences but 

demonstrate the potential hazards to development 

below unstable areas (USFS 2005).

EROSION AND DEBRIS FLOWS

The highly erosive steep slopes of the San Gabriel 

Mountains produce considerable amounts of sand, 

mud, and aggregate that form debris fl ows. Fire 

episodes clear steep slopes of vegetation. During 

the rainy season, the soil from these cleared slopes 

form debris fl ows which can be highly destructive 

to anything in its path.

Los Angeles County has constructed a series 

of massive debris basins along the San Gabriel 

Mountains foothills to protect foothill residents 

from debris fl ows. Even these giant basins can be 

ineffective in stopping debris fl ows.

MINERAL RESOURCES

The study area is rich in a variety of mineral 

resources. The map, Mineral Resources, provides an 

overview of the mineral commodities in the study 

area.

Petroleum

The study area overlies the Los Angeles and Ventura 

oil basins, geologic areas well known for their 

petroleum resources. The source of oil resources is 

primarily lower Pliocene and upper Miocene strata. 

The Miocene Puente formation is particularly rich in 

oil resources. The richness in oil resources is due to 

millions of years of sediment build-up. During the 

Miocene epoch, high organic content was trapped 

and preserved in sediments which led to the 

formation of petroleum. 

The oldest producing fi eld in California is in Pico 

Canyon just west of the study area near Newhall. 

Oil was collected here as early as 1850 (Norris and 

Webb 1992). In the 1920s, Los Angeles County 

was the world’s fi fth largest oil producer. Presently, 

oil production is not nearly as prevalent as it 

was almost a century ago. Substantial oil fi elds 

are located in the Puente and Montebello Hills. 

However, many of these fi elds are now inactive. 

Small-scale oil production still occurs in the Santa 

Clarita Valley and some portions of the Puente and 

Montebello Hills (Los Angeles County Department 

of Regional Planning 2008).

Sand and Aggregate

The highly erosive slopes of the San Gabriel 

Mountains provide a seemingly endless source 

of aggregate which is a necessary ingredient 

in building roads and concrete structures. 

Sand, gravel, and other rock products are the 

most signifi cant mineral resources, exclusive of 

petroleum, in the Transverse Ranges (Morton 1982; 

Dibblee 1982). There are multiple sand and gravel 

operations in the study area. Some of the largest 

are located near the Santa Fe Dam in Irwindale, and 

in the Soledad basin. The Santa Clara River also has 

several aggregate mining operations.
26 Draft San Gabriel Watershed and Mountains Special Resource Study & Environmental Assessment 

San Gabriel Mountains

The San Gabriel Mountains are rich in both metallic 

and non-metallic mineral resources. Most notably, 

Placerita canyon, located on the northwestern 

slopes of the San Gabriel Mountains was the 

discovery site for gold in 1842. Both lode and placer 

gold are associated with the Vincent thrust. Placer 

gold has been harvested in Lytle Creek and the San 

Gabriel River (USFS 2005). 

The two largest gold mines are the Allison Mine on 

the south fl ank of Iron Mountain and the Big Horn 

Mine on the east side of Mt. Baden-Powell (Ehlig 

1982). 

Old terranes in the western San Gabriel Mountains 

have also been mined for gold. Active gold mining 

still takes place near Acton where there are quartz 

vein gold deposits (Morton 1982). Historically, 

minor amounts of gold were obtained from the 

Mount Lowe plutonic suite southwest of Soledad 

Pass (Dibblee 1982).While small amounts of gold 

were mined in basement rocks prior to 1940, most 

have not been profi table.

Other Mineral Resources

Other known commodities in the San Gabriel 

Mountains include aluminum, asbestos, asphalt, 

barite, clays, beryllium, copper, diatomite, feldspar, 

graphite, iron, limestone products, manganese, 

mica, oil and gas, platinum, silica, slab rock, silver, 

titanium, tungsten, uranium, and zirconium (See 

Map: Mineral Resources).

PALEONTOLOGICAL RESOURCES

Paleontological resources are fossilized remains of 

non-human organisms. Many paleontological sites 

include remains of species that are now extinct. 

Southern California has important paleontologic 

(fossil) resources that are sought by collectors, 

universities, and museums. Some of these 

scientifi cally important fossil resources are being 

lost to rapid deterioration and decomposition when 

exposed on the surface, and others are being lost to 

unauthorized collecting. 

Signifi cant paleontological resources are associated 

with the Mint Canyon in Soledad basin, the 

Puente formation in the Puente Hills, and La Habra 

formations (SCAG 2008). Vertebrate fossils in the 

Mint Canyon formation indicate an age of late 

Miocene to early Pliocene. This fauna includes 

merychippus, hipparion, alticamelus, rhinoceroses, 

antelopes, and carnivores (Mount 1971). Fossils 

associated with the Puente formation include fi sh 

and leaves (SCAG 2008).

Water Resources

HISTORICAL ECOLOGY

Rivers and creeks in the study area, primarily in 

the Los Angeles basin, have undergone signifi cant 

changes since European settlement. Because 

changes are most signifi cant in the Los Angeles 

basin, this discussion focuses primarily on the presettlement hydrology of the Los Angeles basin.

Early explorers and surveyors provided detailed 

descriptions of water features on the Los Angeles 

basin. Rivers ran freely across the plain in braided 

channels. Cienegas (swampy areas), many of which 

were fed by springs, were abundant, creating lush 

wet areas throughout the landscape. A series of 

springs were associated with the feature we now 

know as the Raymond fault. 

Rivers and creeks were wide, gravelly channels 

referred to as washes. Many were a half a mile wide 

or more. Within these wide beds, the channels 

would shift during times of fl ooding and heavy 

rains. At the base of the San Gabriel Mountains, 

the deep gravels and groundwater basins absorbed 

water draining from the mountains. Waterways 

would “disappear” into the gravels and rise to the 

surface south of Whittier Narrows (Crespi 2001). 

There are also many historical accounts of how the 

San Gabriel and Los Angeles Rivers often changed 

their courses, creating new channels during fl oods. 

Early maps show both an “Old” and “New” San 

Gabriel River. Coyote Creek, now a tributary to 

the Lower San Gabriel River, drained directly from 

the Puente Hills through the coastal plain to Los 

Alamitos Bay (Hall 1888).

SURFACE WATER

The study area contains portions of fi ve major 

watersheds in the Los Angeles region: the San 

Gabriel River watershed, the Los Angeles River 

watershed, the Santa Clara River watershed, the 

Antelope Valley watershed, and a very small portion 

of the Santa Ana River watershed. (See Map: 

Watersheds).

In the mountains and foothills, coastal watersheds 

feature natural streams with year-round fl ow and 

high quality habitat. Downstream, the urbanized 

Los Angeles basin features river systems that have 

been engineered to protect homes and businesses 

from fl ooding. 

San Gabriel River Watershed

The San Gabriel River watershed encompasses 661 

square miles. Its headwaters are in the San Gabriel 

Mountains and the river reaches the Pacifi c Ocean 
Chapter 2: Resource Description Natural Resources 27
28 Draft San Gabriel Watershed and Mountains Special Resource Study & Environmental Assessment 

at Los Alamitos Bay. The upper San Gabriel River 

subwatershed, Walnut Creek subwatershed, San 

Jose Creek subwatershed, and a small portion 

of the Coyote Creek watershed, are included in 

the study area. The upstream tributaries of the 

watershed have year-round fl ow provided by springs 

and still retain high quality habitat (California 

Coastal Conservancy 2001; California Regional 

Water Quality Control Board 2000).

There are 26 dams in the San Gabriel River 

watershed. Most of the major dams were built after 

the 1930, such as Cogswell Dam (1934), Morris 

Dam (1934), San Gabriel Dam (1939), Santa Fe 

Dam, and Whittier Narrows Dam (1957).The lower 

part of the river (the area generally below Santa Fe 

Dam) is channelized and developed for much of its 

length except at recharge basins where the bottom 

is gravelly. 

Los Angeles River Watershed

The Los Angeles River watershed drains 830 

square miles of land from the Santa Monica 

Mountains, the San Gabriel Mountains, and the 

Los Angeles basin, reaching the Pacifi c Ocean in 

Long Beach. Featuring one of the most extensive 

fl ood protection systems, virtually all of the main 

channel has been channelized and paved to protect 

downstream urban areas from fl ooding. Portions of 

the watershed in the San Gabriel Mountains have 

year-round water supplied by springs and support 

high quality habitat for plants and animals.

The study area contains only the northeastern 

portion of the watershed. This includes portions 

of the upper Tujunga, Pacoima, Arroyo Seco, and 

Rio Hondo subwatersheds. The upper watersheds 

are characterized by steep sloping channels that 

are some of the most prolifi c sediment-producing 

channels in the world. Major upstream dams within 

the study area include the Pacoima and Big Tujunga 

Dams. 

The Rio Hondo River formerly meandered across 

the basin as a channel to the San Gabriel and 

Los Angeles Rivers. The Rio Hondo has now been 

engineered as a permanent tributary to the Los 

Angeles River for fl ood control purposes. 

The Los Angeles River and San Gabriel River 

watersheds are hydrologically connected by the 

Rio Hondo River through the Whittier Narrows 

Reservoir. Much of the Rio Hondo River and its 

tributaries have been channelized and paved. Dams 

in the Rio Hondo drainage area include the Eaton, 

Sierra Madre, Big Santa Anita, and Sawpit Dams 

(LADPD 2006b; California Coastal Conservancy 

2001). 

Santa Clara River Watershed

The Santa Clara River is the largest river system 

in southern California that remains in a relatively 

natural state. Approximately 1,200 square miles 

of this watershed drains to the Santa Clara River 

Estuary in Ventura County. The only major dams in 

the watershed are located outside of the study area 

in the Sierra Pelona Range. No major dams have 

been located on the main river channel. The Santa 

Clara River is the last unchannelized riparian and 

wildlife corridor in the region, providing the primary 

remaining east-west biological connection between 

the San Gabriel Mountains and the Pacifi c Ocean 

(California Coastal Conservancy 2001). 

Portions of the Upper Santa Clara River watershed 

are located in the study area where the Santa 

Clara River originates in the San Gabriel Mountains. 

The Upper Santa Clara River is a large ephemeral 

stream. As the river exits the confi nement of the 

mountains, it has braided stream geomorphology 

characterized by the frequent shifting network of 

channels and the intervening bars, and the broad 

fl oodplain area, and typical of braided stream 

deposits (LADPW 2005).

Santa Ana River Watershed

The Santa Ana River watershed encompasses 2,800 

square miles. Channelization of the river with high 

levee banks and other fl ood control measures 

characterize much of the main channel south of 

the mountains. The only portion of the watershed 

located within the study area is the San Antonio 

Creek in the far eastern end of the study area. 

Below San Antonio Dam, San Antonio Creek is 

channelized. 

Antelope Valley Watersheds

Rivers that drain to the Antelope Valley include 

Little Rock, Big Rock, and Mescal Creeks. All of 

these creeks have intermittent fl ow. Little Rock 

and Big Rock Creek also have subsurface fl ow, 

important to dry lakes in the Mojave Desert (PCR 

Services Corporation 2000a). Little Rock Creek has 

its headwaters in Cooper Canyon and drains to the 

Mojave Desert. It is free-fl owing and very scenic 

from its upper reaches to Little Rock Reservoir. 

Lakes

The San Gabriel Mountains and San Andreas 

rift zone contain natural lakes. These lakes were 

formed by natural sag ponds on the San Andreas 

fault and by landslides in the mountains. 

Una Lake is a natural sag pond, which is an 

enclosed depression formed where active or recent 
Chapter 2: Resource Description Natural Resources 29
30 Draft San Gabriel Watershed and Mountains Special Resource Study & Environmental Assessment 

fault movement along the San Andreas fault 

resulted in impounded drainage. This area has 

extensive wetlands and provides important wildlife 

habitat.

Lake Palmdale was a natural sag pond that was 

impounded in 1924 to create the Harold Reservoir. 

This reservoir provides water for local agriculture.

Jackson Lake, located in the Angeles National Forest 

near the town of Wrightwood, is also a natural sag 

pond in the San Andreas rift zone.

Crystal Lake is an alpine lake found high in the San 

Gabriel Mountains. This natural lake formed from 

one of the largest landslides known in southern 

California. The Crystal Lake area was once a major 

recreational complex of the Angeles National Forest. 

The water is now off limits for swimming because 

of biological contamination. A major fi re in 2001 

destroyed much of the forests around the lake. It 

remains a popular fi shing destination. 

FLOOD PROTECTION AND WATER STORAGE

Flood protection and water conservation planning 

began in the early part of the 20th century following 

a disastrous fl ood event in 1914. A total of 14 dams 

were built to control waters from the San Gabriel 

Mountains. A brief history of Los Angeles County 

fl ood protection and water conservation system is 

described under Cultural Resources.

Extensive fl ood protection and water conservation 

systems were constructed by Los Angeles County 

and the Army Corps of Engineers throughout 

the fi rst half of the 20th century. These structures 

are a dominant feature of the Los Angeles Basin 

landscape. Within the study area there are 29 

dams and debris basins (See Map: Flood Protection 

Facilities). 

The San Gabriel River has fi ve major dams, all 

of which have the dual purpose of both fl ood 

protection and water supply and storage. Other 

major dams on the southern slopes of the San 

Gabriel Mountains include Tujunga, Big Santa Anita, 

Santa Anita, Sawpit, Big Dalton, San Dimas, Live 

Oak, and Puddingstone Dams. Little Rock Dam 

and Harold Reservoir (Lake Palmdale) are the only 

major dams on the north slope of the San Gabriel 

Mountains. Harold Reservoir, created from a natural 

sag pond on the San Andreas fault, is the study 

area’s oldest dam (1891).

In addition to dams, many of the rivers and 

creeks throughout the basin were straightened 

(channelized) and hardened to confi ne the fl ow of 

channels during heavy rains. 

WATER CONSERVATION AND SUPPLY

The importance of the San Gabriel Mountains as 

a water source was apparent to early settlers who 

relied on the mountains to feed water from the 

canyons to farmlands (Robinson1991). The City of 

Pasadena petitioned the California Board of Forestry 

in 1888 to protect the San Gabriel Mountains for 

its watershed values. During this time, excessive 

timbering was impacting water quality and 

destroying mountain springs and watercourses 

used to irrigate the San Gabriel Valley. The State of 

California established the San Gabriel Forest Reserve 

in 1891. Watershed protection was the primary 

impetus for establishing the reserve.

Groundwater

Groundwater basins, or aquifers, are natural 

underground formations fi lled with sediment, 

including sand and gravel. Beneath the study area 

are portions of seven major groundwater basins. 

Wells drilled into the basins provide water for 

municipal use. Local groundwater basins provide 

30% of the region’s water supply on average. These 

basins will supply up to 60% during drought years 

(LADPW 2006a and 2006b). For most of these 

basins, only a portion is located in the study area. 

Table 2 provides a description of the groundwater 

basins within the study area. Also, see Map: 

Groundwater Basins and Water Supply Facilities.

Spreading grounds artifi cially recharge groundwater 

to aquifers by spreading imported water, local 

runoff (including the water impounded by the 

upstream dams during storms), and recycled water. 

Los Angeles County Department of Public Works 

manages 27 spreading facilities throughout Los 

Angeles County.

San Gabriel River Water Conservation 

System

The largest water conservation facilities in Los 

Angeles County are located on the San Gabriel 

River, just south of San Gabriel Canyon and in the 

San Gabriel Valley near Whittier Narrows. The San 

Gabriel River water conservation system begins 

in the San Gabriel Mountains with the capture of 

storm runoff and snow melt in the reservoirs of 

Cogswell, San Gabriel, and Morris Dams. Water 

released through valves or passing over spillways 

when the reservoirs are full can be diverted at the 

mouth of the canyon to the San Gabriel Canyon 

Spreading Grounds or can continue downstream in 

the unlined San Gabriel River toward the Santa Fe 

Dam. In the upper portion of the Santa Fe Reservoir 

is the Santa Fe Reservoir Spreading Grounds. 

Releases from Santa Fe Dam can be spread in the 
Chapter 2: Resource Description Natural Resources 31
32 Draft San Gabriel Watershed and Mountains Special Resource Study & Environmental Assessment 

unlined San Gabriel River downstream with large 

fl ows continuing to Whittier Narrows Dam. Water 

can also be diverted just below Santa Fe Dam and 

routed via Sawpit Wash to Peck Road Spreading 

Basin and the beginning of the Rio Hondo water 

conservation system.

The Whittier Narrows Dam is at the northern 

boundary of the Montebello Forebay. San Gabriel 

River fl ows arriving in the reservoir can be directed 

either to the San Gabriel Coastal Basin Spreading 

Grounds and the downstream unlined San Gabriel 

River, or to the Rio Hondo Coastal Basin Spreading 

Grounds. Any water released from Whittier Narrows 

Dam that is not captured in the Coastal Plain 

spreading facilities fl ows on to the ocean (LADPW 

2004)

Imported Water

Municipal water for the greater Los Angeles 

metropolitan region is supplemented by water 

imported from northern California through the 

State Water Project and from the Colorado River. 

The Metropolitan Water District of Southern 

California, a consortium of 26 cities and water 

districts, receives water from the State Water 

Project.

Recycled Water

Recycled water is used for municipal use such as 

irrigation, industrial applications, environmental 

uses, groundwater replenishment, or maintenance 

of seawater barriers to groundwater basins along 

the coast. The remainder is discharged into creeks 

and rivers, supporting riparian habitat in some 

locations. 

The Sanitation Districts of Los Angeles County 

manage three Water Reclamation Plants (WRP) 

within the study area. These locations include the 

San Jose WRP, the Whittier Narrows WRP, and the 

Pomona WRP.

WATER RIGHTS AND SUPPLY MANAGEMENT

Water rights determine who can draw upon water 

from rivers and groundwater basins and how much 

can be allocated to each user per year. Most water 

supply resources within the study area are fully 

appropriated, meaning the State Water Resource 

Control has determined that all of the water is 

Table 2: Groundwater Basins

Groundwater 

Basin

Surface Area Storage 

Capacity

Recharge Areas

Coastal Plain 

of Los Angeles, 

Central Subbasin

177,000 acres 13,000,000 

acre feet

Precipitation, surface infl ow at Whittier Narrows, , imported 

water, recycled water from Whittier and San Jose Treatment 

Plants, underfl ow from San Gabriel Valley.

San Gabriel Valley 154,000 acres 10,740,000 

acre feet

Precipitation, runoff from surrounding mountains, imported 

water from San Gabriel River, treated sewage effl uent, 

subsurface fl ow from Chino subbasin and fracture systems along 

San Gabriel Mountain front.

Raymond 26,200 acres 1,450,000 

acre feet

Precipitation, streamfl ow from Arroyo Seco, Eaton Creek, and 

Santa Anita Creek, spreading grounds, San Gabriel Mountain 

front fracture systems.

Upper Santa Ana 

Valley, Chino 

Subbasin

154,000 acres 18,300,000

Acre feet

Precipitation, underfl ow from adjacent basins, recharges facilities 

at Deer Creek, Day Creek, East Etiwanda, San Sevaine, and 

Victoria.

San Fernando 

Valley

145,000 acres 3,670,000 

acre feet

Spreading from imported water at the Pacoima, Tujunga, 

and Hanson spreading grounds. Runoff and streamfl ow from 

mountains, precipitation, reclaimed wastewater, and industrial 

discharges.

Acton Valley 

Groundwater 

Basin

8,270 acres 40,000 acre 

feet

Precipitation in the valley, runoff from Santa Clara River and its 

tributaries, and subsurface infl ow.

Antelope Valley 1,100,00 acres 68,000,000 

acre feet

Primarily perennial runoff from surrounding mountains and hills, 

percolation through alluvial fan systems. Big Rock and Little Rock 

Creeks contribute 80% of runoff into the basin.

California Department of Water Resources, 2003
Chapter 2: Resource Description Natural Resources 33
34 Draft San Gabriel Watershed and Mountains Special Resource Study & Environmental Assessment 

owned by water rights holders. The Antelope Valley 

Groundwater Basin has not been adjudicated. At 

the state level, water rights are managed by the 

State Water Resources Control Board. At the local 

level local, agencies and organizations that are 

involved in administering water rights within the 

study area include:

 San Gabriel River Water Committee

 Main San Gabriel Basin Watermaster

 San Gabriel Valley Protective Association

 San Gabriel River Watermaster

 Central Basin Watermaster

 West Coast Basin Watermaster

 Six Basins Watermaster

 Upper Los Angeles River Area Watermaster

Numerous agencies, water districts, and water 

companies are also involved in water supply 

management such as buying, selling, pumping, 

delivery, and clean-up (LADPW 2006b). 

Vegetation 

INTRODUCTION

The diverse landscape of the study area contains 

examples from most of the vegetation types and 

wildlife that are found in Southern California today. 

From the high peaks of the San Gabriel Mountains 

to the low coastal plain south of the Puente-Chino 

Hills, differences in climate, soils, and geology set 

the stage for a wide array of plant communities. 

Alpine, coastal, and desert communities can all be 

found within relatively short distances. These plant 

communities provide habitat to an abundance of 

wildlife.

The study area includes habitat within two distinct 

ecoregions as defi ned by Jepson, the coastal 

Southwestern ecoregion and the Mojave Desert 

ecoregion (see Map: Vegetation). The Southwestern 

ecoregion includes the transverse and peninsular 

ranges and is bordered by the Mojave and Colorado 

deserts to the east and the Mexican border to the 

south. Common plant communities include coastal 

strands and bluff, lagoons, coastal sage scrub, 

chaparral, foothill woodlands, and coniferous 

forests in the mountains. Chaparral is the dominant 

native plant community in the study area and 

throughout southern California’s national forest 

Alluvial fan scrub, Big Tujunga Canyon. Photo courtesy 

of JC Dittes.

White fi r, Islip Saddle, San Gabriel Mountains. Photo 

courtesy of Ryan Gilmore.
Chapter 2: Resource Description Natural Resources 35

system. These chaparral systems are important 

for watershed conservation in southern California 

(Halsey 2008).

The Mojave ecoregion lies north and east of the 

study area and includes one-fi fth of the state. Plant 

communities include desert scrub, Joshua trees, and 

pinyon/juniper woodlands. 

Many of the region’s native plant communities 

have been displaced due to grazing, agriculture, 

and ultimately, urban development. Almost all of 

the native plant communities that remain contain 

sensitive, rare or endangered fl ora and fauna.

This section describes the native and wildlife 

vegetation that existed in the study area when 

European settlers arrived and provides an overview 

of existing vegetation and wildlife found within the 

study area today. 

NATIVE VEGETATION

Although no comprehensive inventories and studies 

of the region’s native vegetation were conducted 

by early Spanish explorers, diaries kept during 

expeditions help paint a picture of the pre-European 

landscape. 

Accounts from Early Explorers 

The fi rst detailed accounts of study area vegetation 

were from the overland expedition led by Captain 

Gaspar de Portola in 1769-1770. Diaries kept by 

Juan Crespi, a padre in the expedition, provide 

some of the most detailed early descriptions of the 

study area’s native vegetation. Crespi describes the 

San Gabriel Valley as lush with dense woodlands of 

willow and oak trees and other species such as rose 

bushes, sage, thistles, grapevines, cumin, and holy 

thistles. He also describes a great swamp, watered 

by a spring-fed river, with many plants and “good 

grasses.” Crespi writes that this area would make 

a “grand, excellent spot for a very large plenteous 

mission” (Crespi 2001).

As the Portola expedition continued north and 

west, they crossed the western San Gabriel 

Mountains and descended into the Soledad Basin. 

Crespi describes the Santa Clara River valley as an 

area having good grass-grown soil and areas with 

large cottonwoods, sycamores, white oaks, willows, 

and vineyards (Crespi 2001).

Early Surveys

In the 1940s, the U.S. Forest Service created a 

detailed map of California’s native vegetation. 

The California State Board of Forestry, in its 

publication, An Historico-Ecological Study of the 

Range Resource of California, amended this map 

after consulting historical records by pioneers, 

travelers, and early residents that observed 

vegetation. According to this document, native 

plant communities of the study area would have 

included: California prairie in the valleys and 

coastal plain; sagebrush in the Puente-Chino Hills; 

sagebrush, chaparral, coniferous woodland, and 

forest in the San Gabriel Mountains; and desert 

scrub in the Antelope Valley (Burcham 1957). 

The vegetation that has changed most dramatically 

since European contact is the California prairie. 

California prairie was found along alluvial areas in 

Southern California in elevations 50 to 500 feet 

above sea level. Soils in these areas are similar to 

soils which underlie Midwestern prairies. In the 

study area, California prairie habitat would have 

dominated in the San Gabriel Valley and coastal 

plain areas south of the Puente-Chino Hills. 

Dominant species were perennial bunchgrasses such 

as purple needlegrass and nodding needlegrass. 

Herbaceous plants such as such as wildfl owers, 

sedges, and bulbs were also common. Today there 

is virtually no remnant of this community apparent 

in the Los Angeles region. Native grasses are 

typically found intermixed with nonnative species 

introduced from Europe. This is a result of the 

California prairie being well suited for grazing and 

irrigated agriculture (Burcham 1957).

John Muir, in his famous book, The Mountains 

of California, describes the vegetation of the San 

Gabriel Valley as fl ourishing with white sage in the 

valleys and low hills, black sage on the mountains 

and streamsides with melilotus, columbine, collinsia, 

verbena, zauschneria, wild rose, honeysuckle, 

philadelphus, and lilies. Wild buckwheat was also 

in great abundance (Muir 1894). Steep hillsides 

in the Puente-Chino, San Jose Hills, and southern 

San Gabriel Mountains foothills would have been 

covered in chaparral and coastal sage scrub. Coastal 

sage scrub, in particular, has been severely reduced 

from its former range as this habitat was very 

suitable for agriculture and ranching.

The other dominant community that has been 

dramatically altered since European settlement 

is the foothill woodland which would have 

intermingled with California prairie and chaparral 

communities. The foothill woodlands were profuse 

in the deep alluvial soils of lower fl ats and hills in 

the Santa Clara River Valley (Soledad basin) and the 

Los Angeles basin. This would include woodlands 

of walnut and oak found in canyons and hillsides, 

and broad corridors of willow, alder, sycamore, and 

mulefat along rivers and creeks (Schiffman 2005).
36 Draft San Gabriel Watershed and Mountains Special Resource Study & Environmental Assessment 

EXISTING VEGETATION AND HABITAT

The vegetation and habitat of the study area are 

primarily described according to the California 

Wildlife Habitat Relationships System (CWHR) 

habitat classifi cation scheme which has been 

developed to support the CWHR System, a wildlife 

information system and predictive model for 

California’s regularly-occurring birds, mammals, 

reptiles, and amphibians.

Grassland

Annual grassland habitat primarily occupies 

what was once California prairie. Introduced 

annual grasses are the dominant plant species in 

this habitat including wild oats, soft chess, red 

brome, wild barley, true clovers, and many others. 

Remnants of native plants and grasses are also 

found in this habitat including California poppy and 

purple needlegrass, and Idaho fescue. 

Characteristic wildlife associated with annual 

grassland include the western fence lizard, common 

garter snake, and western rattlesnake, California 

ground squirrel, California vole, badger, coyote, 

burrowing owl, short-eared owl, and western 

meadowlark. This habitat also provides important 

foraging habitat for raptors such as the northern 

harrier and the prairie falcon (CDFG 2008a).

Within the study area, fragmentary representatives 

of native grasslands exist in the Antelope Valley, 

along the Santa Clara River, eastern San Gabriel 

Valley, San Jose Hills, Puente Hills, and the San 

Gabriel Canyon. The native grasslands in these 

areas are typically occurring in scattered patches.

Vernal pools, small depressions with a hardpan soil 

layer, are also found in grassland habitat. Vernal 

pool systems are extremely rare in Los Angeles 

County. There are only two verifi ed vernal pools 

currently recognized in the region – Cruzan Mesa 

and Plum Canyon. However, there is at least 

one small seasonal pond with typical vernal pool 

characteristics within the study area. Located in 

the upper Placerita-Sand Canyon watershed in the 

Angeles National Forest, this pool supports Riverside 

fairy shrimp and western spadefoot toad (PCR 

Services Corporation 2000a).

Scrub and Chaparral Communities

Coastal Sage Scrub is found at elevations below 

2,500 feet in climates with mild temperatures 

and maritime infl uence. Shrubs are knee high 

with soft fl exible leaves that are often droughtdeciduous (they lose their leaves during the summer 

dry season). Common species include California 

sagebrush, brittle-bush, California buckwheat, and 

Photos (top to bottom): 1. Walnut grove, Puente Hills. 

NPS photo. 2. Rabbitbrush and sub-alpine vegetation on Pine Mountain, Angeles National Forest. Tom 

Chester photo at: http://tchester.org/sgm/plants/pix/

rabbitbrush.html. 3. Chaparral, Angeles National 

Forest. NPS photo. 
Chapter 2: Resource Description Natural Resources 37
38 Draft San Gabriel Watershed and Mountains Special Resource Study & Environmental Assessment 

various types of sage. Coastal sage scrub is one of 

the most threatened communities in California. At 

least 13 rare, threatened and endangered species 

are associated with this habitat (Schoenherr 1992).

The study area contains a wide range of coastal 

sage scrub communities. Three classifi cations of 

coastal sage scrub are typical of the Southwestern 

ecoregion as classifi ed by Axelrod: Venturan, 

Riversidian, and Diegan. A fourth representation, 

coastal sage scrub-chaparral, typically found in 

transitional areas near mountain foothills, has 

been defi ned by Holland. All four variations are 

represented in the study area. Riversidian coastal 

sage scrub is primarily located in the upper Santa 

Clara River watershed. Venturan is found in the San 

Jose Hills, Puente Hills, and San Gabriel Mountains 

foothills. Diegan coastal sage scrub is found in the 

eastern Puente Hills. The Puente Hills represent a 

transition between Venturan and Diegan coastal 

sage scrub. Many of these areas are designated 

habitat for the federally threatened coastal 

California gnatcatcher (Puente Hills Landfi ll Native 

Habitat Preservation Authority 2007; Davis, et al. 

1994, Axelrod 1978).

Desert scrub includes a number of widely spaced 

formations of shrubs and subshrubs which occur on 

open, sandy soils where groundwater is inaccessible 

to all but a few deep-rooted species. Dominant 

species include sagebrush, antelope bush, creosote 

bush, saltbush, rabbitbrush, cheesebush, sages, 

winterfat, and burrobrush. This community 

often inter-grades with juniper and Joshua tree 

woodlands. Primary resident species include 

Couch’s spadefoot toad, desert tortoise, a variety 

of lizards and snakes including desert iguana, 

kingsnake, black-throated sparrow, kangaroo rats, 

and pocket mice (CDFG 2008). Within the study 

area, desert scrub is found on lower slopes within 

the San Andreas rift zone on north facing slopes 

that transition onto the Antelope Valley fl oor, 

interspersed with grasslands (PCR Services 2000a).

Alkali desert scrub communities tolerate alkaline 

soils by absorbing salt and water. Common plants 

include saltbushes, desert holly, sagebrush, and 

alkali golden bush. In the study area, it is found in 

the Antelope Valley and the northern foothills of 

the San Gabriel Mountains. Wildlife associated with 

desert scrub includes the pallid kangaroo mouse, 

chisel-toothed kangaroo rat, zebra-tailed lizard, 

and the San Emigdio blue butterfl y (CDFG 2008a, 

Schoenherr 1992, Mayer and Laudenslayer 1988, 

Davis et al 1998, PCR Services Corporation 2000a).

Alluvial wash and alluvial fan sage scrub generally 

consists of a mixture of shrubs which colonize and 

persist within infrequently scoured and fl ooded 

terrain such as fl oodplains, alluvial plains, or along 

seasonal streams. The dominant shrub in most 

washes is scalebroom. Alluvial fan sage scrub type is 

found in alluvial plains and washes in the Antelope 

Valley, in canyons adjacent to the San Gabriel Valley 

and throughout the alluvial plains and washes of 

the Santa Clara River. It is extremely reduced from 

its historic range as a result of alterations to river 

channels for fl ood protection.

Alpine dwarf scrub is restricted to elevations 

about 10,000 feet in southern California. In the 

San Gabriel Mountains, common species include 

draba, Parish’s alumroot, creambush, rock-cress, 

and species of buckwheat. At its lower extent 

it interfaces with subalpine conifer, closed cone 

pine/cypress, Sierran mixed subalpine forest, and 

southern California subalpine forest. Resident 

wildlife associated with alpine dwarf scrub includes 

blue grouse, pika, rufous hummingbird, and 

mountain sheep (Mayer and Laudenslayer 1988, 

USFS 2005).

Sagebrush typically occurs at a wide range of 

middle to high elevations. This habitat is dominated 

by sagebrush, rabbitbrush, horsebrush, mahogany, 

gooseberry, and western chockeberry. Wildlife 

associated with sagebrush include: migrating mule 

deer, pronghorn, sage grouse, jackrabbit, and 

ground squirrels. Within the study area it is found in 

the Soledad basin and Antelope Valley areas (CDFG 

2008a, Davis et.al. 1994).

Chaparral is the most prolifi c plant community 

in the study area. This community consists of 

sclerophyllous (hard-leafed), medium to tall shrubs 

that form a dense cover on steep slopes, usually 

below 5,000 feet in southern California. Dominant 

species found within this community include 

scrub oaks, chamise, manzanita, wild lilac, toyon, 

and western mountain-mahogany. The study 

area contains chamise-redshank chaparral, mixed 

chaparral, and montane chaparral.

Chamise-redshank chaparral consists of nearly pure 

stands of chamise or redshank. Wildlife species 

associated with this chaparral are similar to those 

associated with sagebrush and coastal sage scrub. 

Within the study area it is abundant in the San 

Gabriel Mountains and southern foothills, the upper 

Santa Clara River watershed, and a few stands in 

canyons of the Puente-Chino Hills (CDFG 2008a, 

Davis et.al. 1994). 

Mixed chaparral is fl oristically diverse and contains 

approximately 240 species. This is the dominant 

type of habitat in the study area and comprises over 
Chapter 2: Resource Description Natural Resources 39

170,000 acres or 25% of the study area landcover. 

Typically associated shrubs include chamise, silktassel, toyon, yerba-santa, California fremontia, 

scrub oak, chaparral oak, and species of ceanothus 

and manzanita. Species found here are those that 

are found in other chaparral habitat, coastal sage 

scrub, and sagebrush. Within the study area, mixed 

chaparral is mostly restricted to the San Gabriel 

Mountains and higher elevations of the Antelope 

Valley (CDFG 2008a, Davis et.al. 1994). 

Montane chaparral is typically associated with 

coniferous habitats such as ponderosa pine, mixed 

conifer forests, Jeffrey pine, red fi r, and lodgepole 

pine. In the San Gabriel Mountains, it is typically 

found at elevations over 7,000 feet. Common 

species include ceanothus, manzanita, huckleberry 

oak, mountain mahogany, toyon, and California 

buckthorn. Montane chaparral provides habitat 

for a wide variety of wildlife including rabbits and 

hares, many types of bird species, and important 

foraging habitat for deer. This habitat is found in 

upper watershed of the San Gabriel River (CFDG 

2008a, Davis et.al. 1994). 

Woodlands and Forests

Coastal oak woodlands are common to coastal 

foothills and valleys. Dominant species in southern 

oak woodlands and forests include coast live oak, 

interior live oak, Engelmann oak, and southern 

California walnut woodlands and forests. Coastal 

oak woodlands provide habitat to a wide variety of 

wildlife including at least 60 mammal and 110 bird 

species in some areas (CDFG 2008a).

In the Puente-Chino Hills area, the dominant oak 

species is the coast live oak. It is found scattered 

throughout many hillsides, drainages, and broad 

valleys. It is most prevalent on north facing slopes 

and in drainage bottoms. Large complexes of 

oak woodland are found in Powder Canyon, Brea 

Canyon, and Tonner Canyon. Throughout the San 

Gabriel Valley and southern San Gabriel Mountains 

foothills, oak woodland is found scattered on north 

facing slopes and in drainage bottoms. The upper 

Santa Clara River watershed contains coast live oak 

woodlands, usually along the margins of canyon 

bottoms and on lower slopes in chaparral and 

coastal sage scrub understory habitats. 

Often intergrading with oak woodlands are walnut 

woodlands. Dominated by the southern California 

black walnut, which grows 10 to 30 feet high, 

walnut woodlands are common on the hillsides of 

Brea and Tonner canyons where they form some 

of the best developed examples of their type 

south of Ventura County in southern California 

and represent the state’s last remaining extensive 

stand of southern California black walnut. Walnut 

woodlands are also found throughout the eastern 

San Gabriel Valley in the San Jose and South Hills 

(PCR Services Corporation 2006, Schoenherr 1992, 

PCR Services Corporation 2000 and 2000d, Quinn 

1990).

Closed-cone cypress is found scattered among 

chaparral and hardwood forests. Typically, 

dominated by single species of closed-cone pines 

or cypress, this habitat grows in areas with rocky 

and infertile soils. Dominant species include 

Piute cypress, cuyamaca, and species common to 

chaparral habitat. Great-horned owls and red-tailed 

hawk roost in this habitat (CDFG 2008a). 

Joshua tree woodland is dominated by Joshua 

trees with numerous smaller shrub species such as 

creosote bush and sagebrush interspersed. Joshua 

trees provide nesting and perching sites for birds 

associated with desert scrub habitat. Within the 

study area, Joshua trees are located on the lower 

slopes in the San Andreas rift zone at the northern 

base of the San Gabriel Mountains (PCR Services 

Corporation 2000a, CDFG 2008). 

Juniper woodlands are dominated by California 

juniper, often with an understory of desert scrub 

species including foothill yucca and buckwheat. 

Within the study area, juniper woodlands are 

typically found on northern slopes of the San 

Gabriel Mountains, lower slopes within the eastern 

portion of the upper Santa Clara River watershed, 

and on lower slopes in the San Andreas rift zone 

where it is mixed with Joshua tree woodland and 

chaparral. Juniper berries are an important food 

source to bird species and the foliage is consumed 

by some mammal species (CDFG 2008a, PCR 

Services Corporation 2006, Davis et.al. 1994).

Pinyon-juniper woodland consists of a mixture 

of single needle leaf pinyon pine and California 

juniper, with mountain mahogany, buckwheat, 

squawbush, foothill yucca, penstemons, and native 

grasses. This habitat is found in the upper Santa 

Clara River watershed and along the northern 

slopes of the San Gabriel Mountains at middle 

elevations (PCR Services Corporation 2006).

Montane hardwood occurs at middle to high 

elevations in the transverse and peninsular ranges. 

Within the study area, it is found in the San Gabriel 

Mountains. At higher elevations, formations 

typically have an overstory of conifers such as 

pines, bicone Douglas fi r, incense-cedar, and 

California black oak. At lower elevations, overstory 

species typically include oaks, white alder, bigleaf 
40 Draft San Gabriel Watershed and Mountains Special Resource Study & Environmental Assessment 

maple, bigcone Douglas-fi r, and California-laurel. 

Understory vegetation usually is dominated by 

chaparral species such as coffeeberry, manzanita, 

and ceanothus. A wide variety of wildlife relies on 

this habitat including jays, woodpeckers, squirrel, 

black bear, mule deer, and various reptiles and 

amphibians (CDFG 2008a, Davis et.al. 1994). 

Montane hardwood-conifer includes both 

hardwood and coniferous trees with very little 

understory. Dominant species include canyon live 

oak, Pacifi c madrone, ponderosa pine, sugar pine, 

and incense-cedar. A transitional habitat between 

mixed chaparral, dense coniferous woodlands, 

montane hardwood, and open woodlands, 

montane hardwood-conifer provides important 

forage for birds and mammals. Amphibians are 

found in more mesic areas of this habitat. Within 

the study area, this habitat is found throughout the 

San Gabriel Mountains (CDFG 2008a, Davis et.al. 

1994).

Jeffrey Pine forest occurs in the San Gabriel 

Mountains between subalpine conifer and pinyonjuniper habitat. The dominant species is Jeffrey pine. 

However, it is also associated with other pines, fi rs, 

incense-cedar, and black cottonwood. Its understory 

primarily includes scrub oak, ceanothus, Sierra 

chinquapin, and manzanita. The species richness 

of Jeffrey pine exceeds that of surrounding habitat. 

Jeffrey pine seeds, bark, and foliage are important 

to wildlife (CDFG 2008, Davis et.al. 1994). 

Lodgepole pine forests occur at high elevations in 

the San Gabriel Mountains. Lodgepole pine forests 

are dominated by this species but occasionally will 

include aspen and mountain hemlock. Understories 

are sparse, consisting of scattered scrubs and herbs. 

Wildlife includes reptiles, amphibians, birds, and 

mammals. Species richness is highest adjacent to 

mountain meadows (CDFG 2008a, Davis et.al. 1994).

Ponderosa pine includes forests with 50% or 

more of this species. Shrub layer species include 

mountain-misery, manzanita, ceanothus, and Pacifi c 

dogwood. This habitat is important for migratory 

deer and California condors. It occurs at higher 

elevations in the eastern San Gabriel Mountains 

(CDFG 2008a, Davis et.al. 1994).

Sierran mixed conifer forests are typically found in 

the Sierra Nevada range. Stands in the San Gabriel 

Mountains and other areas in southern California 

are disjunct populations. Dominant species 

include Douglas-fi r, white fi r, ponderosa pine, 

sugar pine, incense-cedar, and California black 

oak. Understory includes a mixture of deerbrush, 

manzanita, chinquapin, gooseberry, rose, and 

mountain-misery. This habitat has a high degree of 

species richness, providing habitat for 355 species 

of animals (CDFG 2008a). 

White fi r stands are forests which typically include 

80% or more of this species. Located at high 

elevations in the upper San Gabriel River watershed, 

white fi r provides habitat for insect-gleaning birds 

such as grosbeaks, chickadees, western tanagers, 

and warblers (CDFG 2008, Davis et.al. 1994).

Subalpine coniferous forest occurs at the highest 

elevations of the San Gabriel Mountains and is 

dominated by lodgepole pine, limber pine, and 

white fi r. A few alpine plants in southern California 

are narrow endemics (native to and restricted to 

a relatively limited area) while others are widely 

distributed with disjunct populations on peaks in 

the Sierra Nevada Mountains, Great Basin, and even 

in the Rocky Mountains (USFS 2005, Major and 

Taylor 1988, Stephenson and Calcarone 1999).

On high peaks such as Mount San Antonio (10,500 

feet), lodgepole pine forms krummholz, a term used 

for woodlands made up of deformed trees growing 

in widely spaced, low-growing, multi-stemmed 

prostrate mats. Krummholz is an environmental 

response to the harsh alpine growing conditions 

(Major and Taylor 1988; Thorne 1988).

Riparian Communities

The study area contains a wide range of riparian 

habitats including Mojave riparian forest, southern 

coast live oak riparian forest, southern cottonwood 

willow riparian forest, southern mixed riparian 

forest, southern riparian scrub, and southern 

sycamore alder riparian woodland (Davis et. al. 

1998).

Much of the remaining intact riparian habitat in 

the study area is in the San Gabriel Mountains and 

foothills and the upper Santa Clara watershed. 

In the San Gabriel Valley and Los Angeles coastal 

plain, riparian areas exist along river corridors and 

creeks in the Puente-Chino Hills. It is estimated that 

approximately 75% of the historical riverine areas 

associated with the lower San Gabriel River have 

been lost to urbanization and alterations for fl ood 

protection. The greatest losses have occurred in the 

Whittier Narrows area (Stein et al 2007). Remaining 

riparian areas support a high diversity of wildlife 

including threatened and endangered species. 

Wetlands

Lacustrine wetlands or freshwater marsh develop in 

areas of still or slow-moving permanent freshwater 

and is dominated by the perennial, emergent 

cattail. Small areas of freshwater marsh are found 
Chapter 2: Resource Description Natural Resources 41

in Puente Hills valleys, along major drainages, in 

scattered locations along the shorelines of reservoirs 

and natural lakes in the San Gabriel Mountains, 

along slow-fl ow portions of the river and tributaries 

within the upper Santa Clara River, adjacent to 

artifi cially created impoundments used to water 

livestock, and in scattered ponds and irrigation 

ditches throughout the Antelope Valley. 

Wet Meadows. The San Gabriel Mountains support 

small, widely scattered, montane meadows. 

Montane meadows are grass- and herb-dominated 

plant communities within lower and upper 

montane conifer and mixed hardwood-conifer 

forests. Montane meadows are restricted to sites 

where there is a combination of gentle slope 

gradient, relatively impervious bedrock, high soil 

moisture retention, shallow depth to groundwater, 

and fi ne-textured soils. Many meadows form 

along fault zones or other geologic contact points 

that impound groundwater. Some San Gabriel 

Mountains meadows serve as popular recreation 

areas (Stephenson and Calcarone 1999). 

Other Types of Vegetation

Agricultural lands in the study area include 

orchards, irrigated croplands, and ranchlands. Most 

agricultural areas are located in the Antelope Valley, 

although a few areas of the Puente and San Jose 

Hills still have cattle-grazing. Most of the lands in 

the San Gabriel Valley and Los Angeles Coastal 

Plain are developed. Urban woodlands that consist 

primarily of ornamental trees such as eucalyptus, 

Canary Island pine, and jacaranda dominate these 

areas (Schiffman 2005).

Disturbed or barren areas either completely lack 

vegetation or are dominated by ruderal species. 

Ruderal vegetation includes grasses and “weedy” 

herbaceous species, including doveweed, mustards, 

wire lettuce, sow thistle, telegraph weed, Russian 

thistle, dock, yellow star thistle, Australian saltbush, 

and cocklebur. Disturbed areas primarily occur 

throughout the Soledad basin and in the Antelope 

Valley.

SPECIAL STATUS PLANTS

The diverse range of plant communities in the 

study area contains suitable habitat for 77 plant 

species considered sensitive, rare, threatened 

or endangered. Of these 77 species, 53 are 

endemic (See Tables B1 and B2 in Appendix B). 

The study area provides habitat for 5 federallylisted threatened (FT) or endangered (FE) plant 

species described below. See maps: FederallyListed Threatened and Endangered Species and 

Designated Critical Habitat.

Braunton’s milk vetch (FE)

Braunton’s milk vetch (Astragalus brauntonii) is 

associated with fi re dependent chaparral habitats. 

Populations are found only on limestone or wash 

sites following a fi re event. Known only to Ventura, 

Los Angeles, and Orange Counties, the remaining 

populations contain no more than approximately 

20 to 30 individuals and the current total number 

of individuals is estimated to be fewer than 100. 

Within the study area, specimens have been 

found in Monrovia (Clamshell Canyon) and in the 

Puente-Chino Hills. The Clamshell Canyon area is 

designated critical habitat for this species. Threats 

to this species include direct loss from urban 

development, fragmentation of habitat and reduced 

capabilities for sustained ecologic processes, 

fragmented ownership of single populations 

resulting in different landscape treatments, 

alteration in fi re cycles, and extinction from 

naturally occurring events due to small population 

size and low numbers of individuals (USFWS 

2006b).

California Orcutt Grass (FE) 

California Orcutt grass (Orcuttia California) is an 

annual grass associated with vernal pool systems 

in Los Angeles, Riverside, and San Diego Counties. 

Listed as endangered by both federal and state 

governments, this species is in decline. Several 

specimens have been located in the upper Santa 

Clara watershed (CDFG 2000). Threats include 

habitat loss and degradation due to urban and 

agricultural development, livestock grazing, offroad vehicle use, trampling, invasions from weedy 

nonnative plants, and other factors (USFWS 1998).

Nevin’s barberry (FE)

Nevin’s barberry (Berberis nevinii) is an evergreen 

shrub in the barberry family that is endemic to 

southern California. Naturally, this species occurs 

in scattered locations in association with alluvial 

scrub, chaparral, coastal sage scrub, oak woodland, 

and/or riparian scrub or woodland. Specimens in 

the study area are located in the foothills of the 

San Gabriel Mountains. Threats to the long-term 

survival of Nevin’s barberry include the introduction 

of invasive, nonnative plants that compete with 

native species and contribute to combustible fuel 

loads, and fi re management strategies that alter 

natural fi re processes. Designated critical habitat is 

located on U.S. Forest Service and Bureau of Land 

Management lands in Riverside County (USFWS 

2008).
42 Draft San Gabriel Watershed and Mountains Special Resource Study & Environmental Assessment 

Slender-horned Spinefl ower (FE)

Slender-horned spinefl ower (Dodecahema 

leptoceras) is an annual in the buckwheat family. 

Its habitat is older alluvial scrub habitat in southern 

California. Within the study area, populations occur 

in the Santa Clara, Tujunga, and Santa Ana River 

watersheds. Remaining populations are primarily 

threatened by development projects, fl ood control 

activities, sand and gravel mining, and recreational 

uses (CDFG 2000).

Thread-leaved brodiaea (FT) 

Thread-leaved brodiaea (Brodiaea fi lifolia) is a 

perennial herb typically found on gentle hillsides, 

valleys, and fl oodplains in mesic, southern 

needlegrass, grassland plant communities. It is 

threatened by urban development, off-road vehicle 

use, grading, alteration of existing hydrologic 

conditions resulting from fl ood control structures, 

over-grazing, and competition from non-native 

plant species. Designated critical habitat areas are 

located in the southern foothills of the San Gabriel 

Mountains near Glendora and San Dimas where 

they are associated with grassland, coastal sage 

scrub, and mixed chaparral (USFWS 2005c).

Wildlife

Early explorers described the Los Angeles region as 

being rich in wildlife. Father Crespi and Pedro Fages 

of the Portola Expedition described vast numbers 

of antelope, hares, and tracks of other very large 

animals that were present in the San Gabriel Valley. 

Large mammals included coyote, wolf, fox, and 

mantugar (described as a sucking pig). There were 

also many reptiles and amphibians (Crespi 2001, 

Fages 1919). Fages described numerous varieties 

of birds including various kinds of thrushes, and a 

few birds of prey quail, sparrows, mocking birds, 

woodpeckers, vultures, pelicans, herons, ducks, 

divers, mud hens, and others (Fages 1919).

California prairie was also home to both grizzly 

and black bears, ground squirrels, and many other 

small mammals. William H. Brewer, a botanist 

and member of the Whitney geological survey 

expedition, described the San Gabriel Mission as 

being the “adobe for myriads of ground squirrels.” 

Additional prairie animals would have included the 

badger, long-tailed weasel, western meadowlark, 

horned lark, and ferruginous hawk. Small native 

mammals and bears created the soil disturbances 

that constituted an important ecological component 

of the prairie ecosystem (Schiffman 2005).

Today, native wildlife still constitutes the majority of 

the faunal species in the Los Angeles basin. These 

species are recent immigrants from the natural 

chaparral and woodlands on the hillsides and in 

the canyons adjacent to the urbanized plains and 

valleys. Some of these native animal species are 

probably more widespread today than they were at 

the time of European contact (Schiffman 2005).

WILDLIFE CORRIDORS

The San Gabriel Mountains are the largest 

contiguous protected open space area in Los 

Angeles County. Because of the diversity of habitat 

in the mountains, they are a refuge for native 

wildlife. Species include large predators such as 

black bears, mountain lions and numerous coyote. 

Other large mammals include the state-protected 

bighorn sheep and mule deer. Insects include ants, 

grasshoppers, and butterfl ies. Riparian areas feature 

rare and endangered fi sh and amphibian species. 

The only known location for mountain yellowlegged frog is in the San Gabriel Mountains. Other 

reptiles and amphibians that reside here include 

the San Gabriel Mountains slender salamander 

(endemic), western spadefoot toad, coast range 

newt, and the coast horned lizard. Wildlife 

connections to the adjacent Castaic and San 

Bernardino Mountains are important for wildlife 

diversity and migration.

Another important regional wildlife corridor is the 

connection between the San Gabriel Mountains 

and the Sierra Pelona Range. The Agua Dulce 

Canyon in Soledad basin provides an important 

wildlife corridor between these two large protected 

areas. As the only major river in southern California 

without any dams on its main channel, the Santa 

Clara River functions as an important corridor 

between the mountains and the ocean. Protecting 

this corridor is a high priority for local and state 

agencies as well as conservation groups. 

The Puente-Chino Hills are part of an important 

regional wildlife corridor. Together, the PuenteChino Hills and Santa Ana Mountains encompass 

about 511,000 acres of wildlands which contain 

biological resources of statewide and worldwide 

signifi cance (Noss, Beier and Shaw, n.d.). This 

wildlife corridor contains many of the rare and 

endangered ecosystems of the southern California 

region including coastal sage scrub, alluvial fan 

sage scrub, grasslands, Southern California walnut 

woodlands, big-cone Douglas fi r forest, and 

Engelmann oak woodlands (Noss, Beier and Shaw 

n.d.). 

Encroachment by roads and development threatens 

habitat connections. Fragmentation of the wildlife 

corridor from encroaching development impacts 

wildlife diversity. Mammals, which are top predators 
Chapter 2: Resource Description Natural Resources 43

(mountain lions, coyotes and bobcats), are the most 

threatened by fragmentation.

“The Puente-Chino Hills/Santa Ana Mountains 

complex provides an archipelago of natural 

open space thrust into one of the world’s largest 

metropolitan areas. As such, their value for 

biodiversity conservation, environmental education, 

outdoor recreation, and scenic beauty are immense 

(Noss, Beier and Shaw n.d.).”

Protecting this wildlife corridor is a high priority for 

local and state agencies. In 2006, a 20-foot wide, 

160-foot long concrete tunnel in the Puente Hills 

was installed beneath Harbor Boulevard to provide 

a safe crossing for wildlife moving between Whittier 

Narrows and the Santa Ana Mountains. 

SPECIAL STATUS WILDLIFE

A high concentration of sensitive wildlife is present 

in the study area, which provides habitat for 

approximately 116 species considered sensitive, 

rare, threatened or endangered (See Tables B1 

and B3 in Appendix B). Eleven of these species are 

federally listed threatened (FT) or endangered (FE) 

animals (See maps: Federally Listed Threatened 

and Endangered Species and Designated Critical 

Habitat).

Arroyo Toad (FE) 

Arroyo toads (Bufo microscaphus californicus) are 

found in seasonal pools and streams where natural 

disturbance is common. A highly sensitive species, 

arroyo toads are known to have one of the most 

specialized habitat requirements of any amphibian 

found in California. Shallow breeding pools with 

a minimum of silt, and free of predatory fi sh, are 

necessary for successful juvenile development 

(CDFG 2000).The arroyo toad is threatened 

by urban development, agriculture, and water 

diversions and was listed as endangered in 1994. 

Critical habitat has been designated for streams in 

the San Gabriel Mountains (Big Tujunga Creek and 

Little Rock Creek). The only known population in 

Antelope Valley is on Little Rock Creek above the 

Little Rock Reservoir (PCR Services 2000a, USFWS 

2005a). 

California Condor (FT)

Suitable habitat for condors (Gymnogyps 

californicus) includes foothill rangeland and forest 

in remote areas where the birds can roost and nest 

in tall trees and on cliffs. Rock outcrops in the San 

Gabriel Mountains provide suitable habitat for 

condors. Condors once considered extinct from 

this region have been sighted in the San Gabriel 

Mountains (CDFG 2008a and USFS 2005).

Coastal California Gnatcatcher (FT) 

The coastal California gnatcatcher (Polioptila 

californica californica) is an insect-eating bird 

that typically occurs in or near coastal sage scrub, 

alluvial fan sage scrub, southern coastal bluff 

scrub, and coastal-sage chaparral. This subspecies 

is restricted to coastal southern California and 

northwestern Baja California, Mexico. Considered 

locally common in the mid-1940s, by the 1960s, 

the gnatcatcher experienced a signifi cant 

population decline in the United States that has 

been attributed to widespread destruction of its 

habitat. Critical habitat for the coastal California 

gnatcatcher includes areas of the western San 

Gabriel Mountains, the San Jose Hills, the southern 

San Gabriel Mountain foothills east of Azusa, the 

Montebello Hills, Whittier Narrows, and the PuenteChino Hills (USFWS 2007).

Desert Tortoise (FT)

Desert tortoise occupy desert scrub habitat in 

California, Nevada, Arizona, and southwestern 

Utah. Small numbers of desert tortoise occur along 

the northern edge of the San Gabriel Mountains. 

The U.S. Fish and Wildlife Service determined 

that the Mojave population of desert tortoise 

was threatened in 1990. The desert tortoise was 

listed in response to the loss and degradation 

of habitat caused by urbanization, agricultural 

development, recreational use, military training, 

mining, and livestock grazing. Individual species are 

also threatened by collision with automobiles and 

collection by humans for pets (USFS 2005).

Mountain Yellow-legged Frog (FT) 

Mountain yellow-legged frogs (Rana mucosa) are 

diurnal frogs that occupy shaded streams with cool 

water from springs or snowmelt. Historically, the 

mountain yellow-legged frog was found throughout 

southern California on both the coastal and desert 

slopes of the San Gabriel, San Bernardino, San 

Jacinto, and Palomar mountains. Current surveys 

show that the frog has disappeared from most of 

its historical range in southern California. Most of 

the remaining populations are located in isolated 

headwater streams in the San Gabriel Mountains 

(USFWS 2005b). Designated critical habitat for the 

mountain yellow-legged frogs includes the East and 

North Forks of the San Gabriel River, the South Fork 

of Big Rock Creek, Little Rock Creek, Devil’s Canyon, 

Day Canyon, and Bear Creek (USFWS 2006a).

Least Bell’s Vireo (FE)

The Least Bell’s vireo (Vireo beliipusillus) inhabits 

riparian woodlands with tall trees and shorter 
44 Draft San Gabriel Watershed and Mountains Special Resource Study & Environmental Assessment 

thick shrubs. Loss of riparian habitat, urbanization, 

non-native species invasion and predation, and 

long-term camping threaten the Least Bell’s vireo. 

Riparian areas within the study area contain suitable 

habitat for the Least Bell’s vireo (USFWS 1994).

Red-legged Frog (FT)

California red-legged frogs (Rana aurora draytonii) 

inhabit shrubby riparian areas and deep, slow 

moving water. Threats to the California red-legged 

frog include habitat degradation, off-road vehicles, 

reservoir construction, grazing, non-native aquatic 

predators, and water quality. Critical habitat for 

the red-legged frog was designated in 2006. A 

population of California red-legged frogs was 

recently discovered in the Angeles National Forest 

after the 2009 Station Fire (USFWS 2010, USFS 

2010).

Southwestern Willow Flycatcher (FE)

The southwestern willow fl ycatcher (Empidonax 

trailii extimus) is a small insectivorous bird that 

makes its home in dense riparian areas in the study 

area. Nesting takes place primarily in thick riparian 

stands of willows or coast live oaks. Threats such 

as cowbird parasitism and habitat destruction from 

urban, recreational, and agricultural development 

have reduced the species so that, on the California 

coast, they can only be found in small isolated 

populations. Major threats to this species include 

loss of habitat and nest parasitism by the brownheaded cowbird (USFWS 1995).

FISHERIES

The Los Angeles basin was home to at least seven 

native species of freshwater fi shes that have been 

declining or have been extirpated since the 1930s. 

Steelhead (Oncorhynchus mykiss), the Pacifi c 

lamprey (Lampetra tridentata), the Pacifi c brook 

lamprey (Lampetra cf. pacifi ca), and the unarmored 

threespined stickleback (Gasterosteus aculeatus 

williamsoni) have been extirpated from the Los 

Angeles basin since the 1950s. Two others, the 

Santa Ana speckled dace (Rhinichthys osculus), and 

the arroyo chub (Gila orcutti), have become rare in 

the Los Angeles basin (Swift. et al. 1993; USFWS 

2004).

Historically, the San Gabriel River was the most 

abundant trout stream in southern California 

(Robinson 1946). The West, North, and East forks 

of the San Gabriel River and their tributaries contain 

highly signifi cant aquatic habitats. Low-elevation 

portions of these streams provide refugia for a 

number of sensitive native fi sh species, including 

the Santa Ana sucker, Santa Ana speckled dace, 

and arroyo chub.

Photos (top to bottom): 1. California gnatcatcher. 

Photo courtesy of BonTerra Consulting. 2. Pacifi c 

gopher snake, Angeles National Forest. Eric Lowenback 

photo. 3. Mountain yellow-legged frog. Photo courtesy 

of BonTerra Consulting.
Chapter 2: Resource Description Natural Resources 45
46 Draft San Gabriel Watershed and Mountains Special Resource Study & Environmental Assessment 
Chapter 2: Resource Description Natural Resources 47

The largest remaining population of arroyo chub 

is reported from the West Fork of the San Gabriel 

River and the largest remaining population of Santa 

Ana speckled dace are on the lower reaches of 

the East, North, and West forks (Swift et. al. 1993, 

Stephenson and Calcarone 1999).

Because of stocking, rainbow trout (Oncorhynchus 

mykiss) are the most abundant species of fi sh 

found in the San Gabriel River drainage system. 

Populations occur on the West, North, and East 

forks of the San Gabriel River, and in both San 

Gabriel and Cogswell Reservoirs. Average densities 

of over 3,500 fi sh per mile were recorded on the 

West Fork (Deinstadt et. al. 1990). The upper San 

Gabriel River drainage is the most heavily stocked 

river system in the Los Angeles Basin, with more 

than 60,000 rainbow trout introduced annually into 

these waters from October through June. 

The Santa Clara River also supports important 

habitat for native fi sh including southern 

steelhead, unarmored three-spine stickleback, 

tidewater goby, Santa Ana sucker, and arroyo 

chub (LADPW 2005). The Tujunga River Watershed 

supports both the Santa Ana sucker and arroyo 

chub (The River Project 2006).

SPECIAL STATUS FISH SPECIES

Santa Ana Sucker (FE)

The Santa Ana sucker (Catostomuss antaanae) is 

endemic to the Los 

Angeles River, the San Gabriel River, and the Santa 

Ana River. Habitat requirements include clean, 

clear, and relatively cool streams of varying width 

and depth with a mix of substrates including sand, 

gravel, cobble, and boulders. 

This species is now restricted to three 

noncontiguous populations in: Big Tujunga Creek; 

the East, West, and North Forks of the San Gabriel 

River; the lower and middle Santa Ana River; and 

the Santa Clara River Watershed. The Santa Clara 

River population of Santa Ana sucker is presumed 

to be an introduced population. The East, North, 

and West forks of the San Gabriel River are all 

designated as southern California arroyo chub/

Santa Ana sucker streams in the California Natural 

Diversity Database (CDFG 2006). 

The population in the San Gabriel River drainage 

system is considered to be the only viable population 

within the species’ native range. Threats to the Santa 

Ana sucker include urbanization, water diversions, 

dams, introduced competitors and/or predators, and 

other human-caused disturbances likely are playing a 

role in the decline of the species (USFWS 2004).

Southern Steelhead (FE) 

Southern steelhead (Oncorhynchus mykiss irideus) 

are winter-run steelhead whose native habitat 

occurs in basins along the southern California 

coast. Steelhead require quality freshwater, marine, 

and estuarine ecosystems to support a healthy 

population, and therefore serve as an important 

indicator of watershed health. The coastal 

watersheds of the study area provide essential 

habitat for steelhead.

Native southern steelhead were historically reported 

from the San Gabriel River, but are now extinct as a 

result of major habitat modifi cation or blockage of 

stream ways associated with fl ood control, urban 

development, and other factors. While the West 

Fork currently supports a productive, self sustaining 

“wild” trout population, this condition is a result of 

past stocking programs. 

All tidally infl uenced waters within the study 

area are designated in the 1996 amendments 

to the Magnuson-Stevens Fishery Management 

and Conservation Act as “Essential Fish 

Habitat.”Additionally, the study area is part of 

the Southern California Evolutionarily Signifi cant 

Unit (ESU). An Evolutionarily Signifi cant Unit is a 

distinctive group of Pacifi c salmon, steelhead, or 

sea-run cutthroat trout (NOAA 2002). 

Unarmored Threespine Stickleback (FE)

The unarmored threespine stickleback (Gasterosteus 

aculeatus williamsoni) is a small, scaleless, native 

fi sh that resides in slow water creeks along the 

California coast. It is endangered in its native 

habitat, the western and northeastern seaboards 

of the United States. Within the study area 

the stickleback is found in the Soledad basin 

in several tributaries of the upper Santa Clara 

River (CDFG 2000).Threats include habitat loss 

through stream channelization, increased water 

turbidity, introduction of nonnative competitors, 

water pollution, aquifer draw downs, and beaver 

activity. Critical habitat for the stickleback has been 

proposed for portions of the upper Santa Clara 

River and several of its tributaries (USFWS 1980).
48 Draft San Gabriel Watershed and Mountains Special Resource Study & Environmental Assessment 

Signifi cant Ecological Areas

Through the Signifi cant Ecological Areas program, 

Los Angeles County has designated and proposed 

areas of high priority for regional conservation. 

County signifi cant ecological areas include those 

areas that contain:

 Rare, endangered, or threatened plant or 

animal species

 Biotic communities, vegetative associations, 

or habitat that are either one-of-a-kind, or 

restricted in distribution on a regional basis

 Habitat that serves as a concentrated 

breeding, feeding, resting, or migrating 

grounds, and is limited in availability 

 Biotic resources that are of scientifi c 

interest because they are either an extreme 

in physical/geographical limitations, or 

they represent an unusual variation in a 

population or community

 Areas important as game species habitat or 

as fi sheries

 Areas that would preserve relatively 

undisturbed examples of the natural biotic 

communities in Los Angeles County

Existing signifi cant ecological areas in the study 

area include Tonner Canyon/Chino Hills, Power 

Canyon/Puente Hills, Whittier Narrows Dam County 

Recreation Area, Sycamore and Turnbull Canyons, 

Buzzard Peak/San Jose Hills, Santa Clara River, 

Santa Fe Dam Floodplain, Dudleya Densifl ora and 

Gallium Grande populations (San Gabriel Canyon), 

San Dimas Canyon, San Antonio Canyon Mouth, 

Big Rock Wash, Little Rock Wash, Desert Montane 

Transect, and the Rio Hondo Wildlife Sanctuary. 

Los Angeles County has proposed new additions 

and expansions to many of these areas in its draft 

General Plan (2008).

Eff ects of Fire

Fire is part of the natural ecology in southern 

California. Many of the plant communities 

have adapted to natural fi re regimes, averaging 

anywhere from 30 to 200 year intervals in southern 

California. Over the last two decades, human 

activities have caused fi re to occur much more 

frequently. Frequently occurring anthropogenic 

fi re as a result of urbanization is currently the 

most important disturbance factor responsible 

for displacing native scrub lands. Although many 

believe that communities such as chaparral and 

coastal sage scrub are fi re-dependent, they are 

highly threatened by these frequent fi res (Keeley 

2005, Halsey 2008). 

In fall of 2009, the San Gabriel Mountains 

experienced the largest wildfi re on record to affect 

the Los Angeles region. Determined to be caused by 

arson, the fi re burned approximately 161,000 acres, 

all within the study area. Approximately 154,000 

acres of the burned lands were part of the Angeles 

National Forest and 6,700 acres were private lands.

The Burned Area Emergency Response (BAER) 

Assessment team evaluated Soil Burn Severity 

for national forest and private lands. The initial 

assessment was made in 2009 and a follow-up 

assessment was made after initial recovery efforts 

in 2010. Approximately 73 percent of the burn 

area was mapped as having a moderate or high 

soil burn severity (62% moderate and 11% high). 

The remaining 27% was either low soil burn 

severity or unburned. 

Thirty seven plant communities were burned or 

impacted by suppression activities during the fi re. 

In addition, the burned area includes occupied and 

potential habitat for one federal endangered plant 

species and eleven Forest Service sensitive plant 

species. Some of these habitats and species are at 

risk to further losses due to habitat loss. 

Recent BAER team evaluations indicate the native 

vegetation within the burn area is recovering well 

due to a combination of factors. These include the 

native vegetation’s adaptation to fi re, the fi re return 

interval being over 30 years in many of the burned 

areas, and the average rainfall year. Burn areas that 

seem to be experiencing a slower recovery are those 

locations where the factors listed above have not 

occurred simultaneously. These areas primarily occur 

on the drier, northern slopes composed of desert 

transition chaparral and California juniper/pinyon 

pine scrub, which are adapted to longer fi re return 

intervals (50-200 years) and typically recover more 

slowly post-fi re. 

The most signifi cant negative infl uence upon the 

vegetation recovery throughout the burn area is the 

abundance of nonnative plant species. Illegal offhighway vehicle activity can exacerbate the spread 

of nonnative species further hampering vegetation 

community recovery.

The BAER Report predicted that post-fi re events 

would lead to the potential injury or mortality 

of threatened and endangered species. The 

modifi cation of streams by post-fi re sediment loads 

is a major threat to species such as arroyo toad, 

California red-legged frog, mountain yellow-legged 

frog, western pond turtle, Santa Ana sucker, arroyo 

chub, and Santa Ana speckled dace. Many historic 

pools that functioned as habitat are now fi lled with 

sediment. In some areas, the stream channels have 
Chapter 2: Resource Description Natural Resources 49

become braided or the active channel has shifted to 

a new location. Rescue teams were able to salvage 

and relocate some threatened and endangered 

species to other suitable habitat sites in the region 

(USFS 2010).

The following treatments were recommended for 

the Station Fire burned area by BAER team: 

• Installing gates and signs for the forest closure 

areas

• Stabilizing hazardous material sites

• Salvaging threatened and endangered species

• Forest closure patrol and enforcement, and 

stabilization of cultural resource sites

• Restoring burned wildlife habitat

• Treating pre-existing noxious weed infestations 

and installing interpretive signs

The Puente-Chino Hills also experienced a 

signifi cant fi re in November 2008, the Freeway 

Complex Fire. Approximately 30,300 acres were 

burned, including 90% of Chino Hills State Park. 

Although many of the important habitats in Chino 

Hills State Park were impacted by this fi re, in 

Spring of 2009, many habitats were beginning to 

recover. One of the largest threats to this recovery 

is the potential of another fi re before the plant 

communities have a chance to reestablish.

Land Use Condition and Change

Portions of the study area landscape have changed 

dramatically since European contact in the 18th 

century. Early explorers encountered braided rivers, 

natural springs (cienegas), prairie grasslands, 

thick woodlands, coastal scrub, and dense 

chaparral forests. Today, many of the native plant 

communities have been replaced by nonnative 

species from other locations. This is especially 

true of the Los Angeles basin where most of the 

native vegetation has been altered by grazing, 

cultivated agriculture and ultimately, conversion 

to urban land uses. Rivers and creeks that once 

roamed freely from the mountains and crossed 

over the plains have been altered by dams and 

engineered channels to prevent fl ooding of homes 

and businesses and to provide water for irrigation, 

domestic, and industrial uses. 

While the canyons and foothills of the San Gabriel 

Mountains were used for timber, irrigation, and 

grazing during dry periods, higher elevations were 

less impacted given the diffi culty associated with 

gaining access to the steep slopes, rough terrain, 

and thick chaparral forests.

With the completion and continued implementation 

of the fl ood control plans, and the importation of 

water to the region, more areas of the Los Angeles 

Basin became available for urbanization. The chart 

Station Fire in the San Gabriel Mountains, 2009. NPS Photo.
50 Draft San Gabriel Watershed and Mountains Special Resource Study & Environmental Assessment 
Chapter 2: Resource Description Cultural Resources 51

below depicts the rapid urbanization that took 

place since 1920 and that continued following 

World War II. Since 1940, Los Angeles County 

population increased by 240%. 

Remaining open spaces are primarily found in 

the mountains and hills of the region which were 

more costly areas to build in. These lands remain 

important wildlife corridors and destinations for 

recreation. See Map, Land Use for area land use as 

of 2001. Current land use trends are described in 

Chapter 7, Environmental Consequences. 

Los Angeles County Population Growth Chart 1900 - 2000
52 Draft San Gabriel Watershed and Mountains Special Resource Study & Environmental Assessment 

Cultural Resources

Introduction

The San Gabriel Watershed and Mountains area 

includes rich and diverse cultural resources that 

represent many layers of history in the region. 

This history includes the settlement of Native 

Americans, Spanish missionaries and colonialists, 

Mexican rancheros, and Euro-American settlers. 

Many cultural resources within the study area 

represent the settlement and growth of southern 

California. The distinctive regional environment, 

such as mountain passes and riverways, played a 

role in determining migration routes and settlement 

patterns. Native American trails, exploration routes, 

as well as trade and emigration routes from the 

east, traverse the study area. Later, railroads and 

highways such as Route 66 would also provide 

migration routes through the study area. 

Cultural resources in the region include prehistoric 

archeological sites, historic sites, and historic 

landscape elements related to ranching, agriculture, 

mining, settlement, and transportation. 

Overview of Cultural Resources:

Resources with national designations:

• Portions of the Juan Bautista National 

Historic Trail, the Old Spanish National 

Historic Trail, Route 66 Corridor, and the 

Pacifi c Crest Trail.

• Upton Sinclair House National Historic 

Landmark (NHL)

• Other sites that have been nominated or 

have potential for listing as NHLs include 

the Mount Wilson Observatory and the 

San Dimas Experimental Forest both in the 

Angeles National Forest. 

• A theme study on large federal dams found 

that the Los Angeles County Flood Control 

System may be nationally signifi cant for its 

impact on the history and development of 

the region.

Resources with state and local designations 

(National Register of Historic Places, California 

Register, or other local listings):

• There are eight properties listed on the 

National Register of Historic Places at the 

state level of signifi cance. An additional 2 

sites are listed on the California Register.

• There are 17 State Historic Landmarks and 

21 State Points of Historical Interest

• There are 31 properties listed on the 

National Register of Historic Places at the 

local level of signifi cance.

• There are 90 additional properties recognized as historically signifi cant by local 

governments.

• There are 135 historical sites within the 

study area that appear eligible for listing 

on the National Register of Historic Places, 

California Register, or other local listing as 

individual sites and contributors to a district. 

Most of these sites need survey evaluation 

to determine eligibility.

• In addition, there are 106 sites that need to 

be reevaluated to determine whether they 

have potential for listing on the National 

Register of Historic Places, California 

Register, or local listing/designation.

Pictographs in the San Gabriel Canyon. 1937. Photo 

courtesy of the Los Angeles Public Libarary. 
Chapter 2: Resource Description Cultural Resources 53

Prehistory

EARLY HUMAN OCCUPATION

Prior to historic contact in 1769, Native Americans 

occupied the region for at least 12,000 years. Some 

Native American groups moved from the inland 

deserts to coastal areas which had a more suitable 

environment. 

Archeological evidence shows that human 

occupation of the Los Angeles basin appears to 

have been continuous since its beginning, though 

not necessarily by the same peoples. Sites identifi ed 

on the Channel Islands and near the Los Angeles 

coast indicate that portions of the study area 

were occupied or in use during the Paleo-Indian 

Period. To the east of the study area, the earliest 

component of the Sayles Site at Cajon Pass, which 

links the Los Angeles basin with the Mojave Desert, 

has been dated to approximately 6,000 years. 

Archeological evidence within the Angeles National 

Forest date to at least 6,000 years ago (USFS 1986). 

NATIVE AMERICAN SETTLEMENTS 

Many Native American villages (both primary and 

seasonal settlements) were located in the Los 

Angeles basin and in mountain canyons (Raab 

2005; Robinson1991). Settlements were adjacent 

to, or near, freshwater sources, including the San 

Gabriel River’s banks. Interior groups are presumed 

to have had access to coastal resources either 

directly or through trade, though historic references 

refer to inter-village confl icts in which “inland 

Gabrielino were effectively prevented by coastal 

Gabrielino from reaching the sea for fi shing and 

trading purposes” (Bean and Smith 1978). 

NATIVE AMERICAN GROUPS

Tongva

The Tongva were the predominant native group 

in the Los Angeles basin from the time of their 

settlement to their incorporation into the Spanish 

missions. The Tongva arrived around 2,500 

B.P. (before present day), slowly displacing the 

indigenous Hokan speakers. The Tongva, with 

the exception of the Chumash, became “the 

wealthiest, most populous, and most powerful 

ethnic nationality in aboriginal southern California” 

(Bean and Smith 1978, Robinson 1991). The Tongva 

were also known as Gabrielinos because of their 

incorporation into Mission San Gabriel.

The Tongva were active hunters, artisans, traders, 

and fi shermen. They made trails throughout the 

mountain areas and traveled seasonally to take 

advantage of the region’s resources (Johnston 

1962). The Tongva used the San Gabriel Mountains 

for hunting deer, mountain sheep, and smaller 

mammals, and for gathering acorns, pinyon nuts, 

yucca, sage, and other plants and seeds. The San 

Gabriel River provided a means for transportation, 

sustenance, and farming.

The Tongva territory and other areas where they 

had activities included Los Angeles County south 

of the crest of the San Gabriel and Santa Monica 

Mountains, half of Orange County and the islands 

of San Clemente, San Nicolas, and Santa Catalina 

(Bean and Smith 1978; Kroeber 1976). 

It is diffi cult to estimate the Tongva population. 

According to some estimates, their population 

exceeded 5,000 at the time of contact. It is possible 

that there were 50 to 100 mainland villages. 

Houses were large, domed, circular structures 

thatched with tule, fern, or carrizo. Archeologists 

have identifi ed approximately 155 aboriginal sites 

in the mountains; most were seasonal camps for 

hunting and gathering. Permanent villages were 

usually along streams or close to springs and 

marshes. Asuksangna was a large Gabrielino village 

located on a knoll just outside the mouth of San 

Gabriel Canyon and north of the city of Azusa 

(Johnston 1962; Bean and Smith 1978; Robinson 

1991). Evidence of permanent Tongva settlement 

has been found at several places in the North, 

East, and West forks of the San Gabriel (Robinson, 

1946). The Awingna site, located on the banks of 

San Jose Creek, continued to exist after Rancho La 

Puente was established. Winingna occupied the city 

of Covina (Johnston 1962). See graphic, “Native 

American Villages.”

Tataviam

The Tataviam territory was located to the north of 

the Tongva and was centered in the San Fernando 

Valley (Kroeber 1976). Their territory included the 

upper Santa Clara River drainage east of Piru Creek, 

extending over the Sawmill Mountains to the north 

to include at least the southwestern fringes of the 

Antelope Valley. Mount Gleason in the San Gabriel 

Mountains, at 6,500 feet, was the highest point 

in their territory (Bean and Smith 1978; Robinson 

1991). Tataviam villages varied in size from large 

centers to small settlements. At the time of contact, 

the Tataviam population was most likely fewer than 

1,000 people. The Tataviam were also referred to as 

the Fernandeños because of their incorporation into 

the San Fernando Mission. The Tataviam differed 

slightly in speech from the Tongva, but were usually 

grouped with the Tongva due to the similarity of 

their culture and practices (Bean and Smith 1978). 
54 Draft San Gabriel Watershed and Mountains Special Resource Study & Environmental Assessment 

In recent archeological studies, the Tataviam have 

been considered a part of the Tongva culture 

(Robinson 1991).

Other Native American Groups

Other Native American groups in the region did not 

have settlements within the study area, but traded 

with the Tongva and Tataviam, traveled through 

their territories, or became incorporated with them 

in the missions. These groups include the Chumash, 

whose expansive territory was to the west; the 

Serrano (Indian mountaineers), who occupied the 

eastern end of the San Gabriel Range and the 

San Bernardino Mountains; the Kitanemuk, who 

were principally in the Tehachapi Mountains and 

occupied the major portion of the Antelope Valley; 

and the Kawaiisu, who occupied the land to the 

east of the Kitanemuk in the higher Sierra Nevada 

(Robinson 1946 and 1991; Bean and Smith 1978; 

Kroeber 1976).

NATIVE AMERICAN LANDSCAPE MANAGEMENT

There are several views on the impact the Native 

Americans had on the landscape based on different 

archeological research and historical accounts. 

These views range from passive hunter/gatherer 

with little impact on the landscape to societies 

where active landscape management through 

burning practices and quasi-agricultural production 

was common (Raab 2005). 

According to one theory now gaining broad 

acceptance, Native Americans used fi re to 

manage the landscape, playing a very active 

role in maintaining the diversity of native plant 

communities. Fire was used to clear forests for 

growth of certain plants needed for food and fi ber 

and to improve forage for game animals. There are 

numerous accounts of the intentional burning by 

the Native Americans in descriptions by the 18th

century explorers (Blackburn and Anderson 1993).
Chapter 2: Resource Description Cultural Resources 55

PREHISTORIC ARCHEOLOGICAL RESOURCES

The study area contains hundreds of prehistoric 

archeological sites, with more being recorded each 

year, many of which represent the Tongva.

Prehistoric sites include permanent and seasonal 

habitation sites of various sizes with midden soils. 

Some habitation sites may be associated with 

rock shelters. Smaller food processing or tool 

manufacturing sites such as bedrock mortars and 

lithic scatters may constitute separate sites or 

be located in association with larger habitation 

sites. Rock art sites (pictographs and petroglyphs) 

are also known and are sometimes associated 

with habitation sites. Cultural features typically 

associated with habitation sites include housepit 

depressions and living surfaces (fl oors) representing 

semi-subterranean residential and ceremonial 

structures, earth ovens, stone hearths, rock 

alignments, and accumulations of fi re altered rock. 

Graves consisting of buried human skeletal remains 

with or without associated artifacts are also typical 

of habitation sites.

Much of native southern California material culture, 

such as basketry, was fi ber-based and therefore 

perishable. Artifacts made of stone, bone, and 

shell, are often preserved in archaeological sites. 

They include such objects as: milling stones (ovoid 

to round grinding slabs) and hand stones (manos); 

portable stone mortars and pestles; percussion and 

pressure fl aked lithic artifacts such as projectile 

points, cutting blades, drills and scrapers; steatite 

pipes, vessels and ornaments; a variety of shell 

beads, ornaments and implements; bone basketry 

making implements, seed harvesters and other 

tools; and bird bone whistles, sometimes decorated 

with incised patterns or small split-shell beads held 

fast with asphaltum. Even basketry fragments can 

be preserved if they have been charred or only 

partially carbonized by fi re.

Most of the recorded archeological sites within the 

study area are within the Angeles National Forest. 

Approximately 225 prehistoric sites are located 

within the Forest, not including isolated fi nds of 

individual artifacts. The 7,800-acre Aliso-Arrastre 

Middle and North Special Interest Area, located 

within the Aliso, Arrastre, and Kentucky Springs 

Watersheds on the Santa Clara-Mojave Rivers 

Ranger District, includes numerous prehistoric 

archaeological sites ranging from long-term 

occupation sites to seasonal encampments and 

special-use resource procurement, processing, and 

storage sites. There are stone circle features, many 

of which are interpreted as house rings, storage 

caches, or religious sites. This concentration of 

stone circles may be unique in southern California. 

There are several sites containing cupule rock 

art features. One of these sites is currently being 

nominated to the National Register of Historic 

Places (USFS 2005). A National Register nomination 

has been prepared for rock art sites within the 

forest dating from approximately 4,000-200 B.P. 

Resources include the only remaining Tongva rock 

art site in eastern Tongva territory. 

To the west of the Angeles National Forest, a 

substantial number of sites have been recorded in 

the vicinity of Agua Dulce between the cities of 

Santa Clarita and Acton along Highway 14.

Fewer sites have been recorded in the urbanized 

communities south of the Angeles National Forest 

as a consequence of rapid growth and development 

in the 20th century. Nevertheless, considering the 

area’s relatively dense prehistoric population and 

the presence of freshwater sources such as the San 

Gabriel River and its tributaries, there is reasonable 

potential for fi nding buried or otherwise obscured 

prehistoric sites in the area. Archeological sites 

located within the urban communities include the 

Patricia Ontiveros Adobe Old Fort and the village 

of Sejat. Several sites have also been determined 

eligible for listing on the National Register of 

Historic Places. 

Of the 1,200 archeological sites within the study 

area that have been recorded, approximately 160 

have either been listed, or determined eligible for 

listing, in the National Register of Historic Places 

either individually or as sites contributing to larger 

archeological districts.

Hispanic Period

European exploration into the region during this 

period (1542-1846) had signifi cant impacts on the 

lives of Native Americans. Spanish missionaries and 

explorers forced native cultures to assimilate into 

the European cultural system. This section describes 

the Spanish explorations into this area, the missions, 

ranchos, and associated cultural resources.

Spanish Exploration and the Mission 

System

Explorations and early settlements during the 

late 1700s brought about signifi cant changes to 

the study area landscape, most of which took 

place in the valleys and plains. The Portola and 

Anza expeditions brought livestock and new 

settlements of Europeans and Mexicans through the 

establishment of missions, pueblos (small towns), 

and presidios (military posts).
56 Draft San Gabriel Watershed and Mountains Special Resource Study & Environmental Assessment 

THE PORTOLA EXPEDITION AND EL CAMINO 

REAL

Many Spanish explorers traveled through the study 

area and established settlements. In 1769, the 

expeditions of Don Gaspar de Portola and Padre 

Junipero Serra led to the founding of fi ve missions 

and two presidios. The expedition route, known as 

El Camino Real, crossed through the San Gabriel 

Valley on its way to Monterey. A historical marker 

commemorates the Portola Expedition in Brea 

Canyon, just north of the city of Brea. 

THE JUAN BAUTISTA DE ANZA EXPEDITIONS

Captain Juan Bautista de Anza led two expeditions 

to establish an overland route to connect Sonora, 

Mexico to Alta California. The route was used to 

provide the California settlements with supplies. 

In 1774, Anza left Tubac, Arizona, with soldiers, 

servants, and a herd of cattle and reached Mission 

San Gabriel Arcángel. At this time, the mission 

(Mission Vieja) was in its original location on the 

banks of the Rio Hondo.

In 1775, Anza made a second expedition bringing 

more colonists and livestock. Mission Nueva was 

established at its present location in the city of 

San Gabriel. On January 4, 1776, the expedition 

reached the mission during a fi erce winter storm. 

The colonists remained at the mission for about 

six weeks to rest while Anza, Pedro Font, and 

soldiers traveled to San Diego to help quell a Native 

American rebellion (National Park Service 1996). 

The colonists that arrived on the expedition more 

than doubled the Hispanic population of Alta 

California. With mixed European, Indian, or African 

parentage, the colonists represented diverse cultural 

backgrounds. These infl uences changed the lives 

of the Native Americans. Pio Pico, the last Mexican 

governor of California, was a descendent of the 

expedition colonists (National Park Service 1996). 

Additionally, this expedition also more than doubled 

the livestock numbers by bringing over 1000 

domestic animals (Burcham 1957).

The Juan Bautista de Anza National Historic Trail 

was designated in 1990 to commemorate the 

expedition. The study area includes 19 miles of the 

1,200 mile long national historic trail from Pomona 

in the east to El Monte in the west.

OTHER EXPLORATIONS

Other portions of the region were also explored 

during the late 1700s – early 1800s. Captain Pedro 

Fages traveled through Cajon Pass and along the 

northern foothills of the San Gabriel Mountains 

looking for army deserters, and Father Francisco 

Garces traveled southwesterly and intersected the 

Anza expedition. He camped on the San Gabriel 

River, near present El Monte (Hafen 1954 and 

McIntyre 1986). Father Jose Maria Zalvidea explored 

the Antelope Valley and the Mojave Desert, almost 

circling what is now the Angeles National Forest 

(USFS 1986; Robinson 1946; Leadabrand 1966).

THE MISSIONS

The Spanish established a chain of 21 missions 

and several presidios along the California Pacifi c 

Coast. Mission San Gabriel Arcángel was founded 

in 1771 and Mission San Fernando Rey de España, 

just beyond the study area, was founded in 1797. 

Spanish towns, or pueblos, including El Pueblo de 

Nuestra Señora (Los Angeles), were also established 

(Beck and Haase 1974). 

Mission San Gabriel Arcángel

Mission San Gabriel Arcángel was the fourth 

Spanish mission. The original site of the mission was 

located along the Rio Hondo. It is believed that the 

timber for the Mission came from the San Gabriel 

Mountains. The fi rst Mission buildings were only 

used for a few years. The mission was relocated 

to higher ground 5 miles northeast (presently the 

city of San Gabriel) in 1776 because of excessive 

dampness and fl ooding (King 1975 and 1990).

The missions owned extensive lands within the 

study area. The San Gabriel Mission lands extended 

35 miles south to San Pedro and 62 miles inland to 

the Muscupaibe Range, totaling approximately 1.5 

million acres (King 1990).

The Mission was the center of community life 

and economic development. Religious and festive 

gatherings including wedding fi estas occurred at 

the Mission (Rowland 1948). The Mission was also 

a place of education, including religious study, 

agricultural practices, art, and music.

Land Use during the Mission Period. Mission San 

Gabriel Arcángel became the agricultural leader of 

the California missions. Spanish settlers established 

an irrigation system for the mission and the pueblo 

of Los Angeles. Irrigation water was brought from 

the foothill canyons of the San Gabriel Mountains. 

Water from the San Gabriel River was diverted by a 

brush “toma,” or weir, upstream into a system of 

“zanjas” (ditches) (Robinson 1991; Nelson 1983). 

Native Americans dug and installed clay-tile pipes. 

The native vegetation was well suited to grazing 

and the missions had several ranches for producing 

livestock. For example, Mission San Gabriel owned 

seventeen ranchos for raising cattle and horses, 
Chapter 2: Resource Description Cultural Resources 57

and fi fteen ranchos for raising sheep, goats, and 

pigs (Burcham 1957). By 1832, the San Gabriel 

Mission livestock numbers had grown to 16,500 

cattle, 11,000 sheep, 830 horses, 117 mules, 280 

hogs, and 130 goats. Crops grown on mission lands 

included wheat, other grains, and many vegetables. 

In 1834, the Mission was recorded as having four 

vineyards with over 150,000 vines and over 2,000 

fruit trees. Orange trees planted at the Mission 

were the fi rst citrus grown in Los Angeles County 

(Sugranes 1909; Farnsworth 1883). 

Mission San Fernando

Mission San Fernando, founded in 1797, helped 

to relieve the long journey between missions San 

Gabriel and San Buenaventura (in Ventura). It is 

located west of the study area and south of the 

Angeles National Forest. Like Mission San Gabriel, 

Mission San Fernando supplied the Los Angeles 

pueblo with hides, tallow, cloth, livestock, and other 

goods. It also became a popular stopping place 

for travelers. The 240-foot long convento building, 

built in 1822, is the largest building to survive 

from mission days and the largest adobe building 

in California. The church, damaged severely in the 

1971 Sylmar earthquake, was demolished, and an 

exact replica was built (Engelhardt 1908).

Mission Period Impacts on Native 

Americans

The Tongva culture rapidly declined following the 

establishment of the missions. Between 1770 and 

1830, Native American populations declined from 

an estimated 310,000 to approximately 245,000. 

The greatest factor was the introduction of 

diseases. Other factors included social and cultural 

dislocation, and outright violence (Cook 1978).

Many Native Americans were incorporated in the 

missions (San Gabriel Arcángel, San Fernando, 

and San Juan Capistrano). The Tongva residing 

in the mission lived under a strict church system 

of governance, and were provided a minimal 

education in agriculture, carpentry, cattle-raising, 

reading, and music (Weber 1979). However, 

there were also attempts at resistance. The 1785 

Toypurina Revolt at Mission San Gabriel and 

others at San Diego and the Colorado River were 

organized by leaders who were threatened by 

Spanish colonial activities (Thomas 1989). In the 

end, despite the destruction of native villages and 

cultures, the Tongva peoples survived (Weber 1979).

Mission Period Resources

Construction of the Mission San Gabriel Arcángel 

began during the latter part of the 18th century, 

and was completed in 1800. It remains in the city 

of San Gabriel. Other remaining structures include 

mills. The 1816 Old Mill, “El Molino Viejo,” located 

in San Marino, was designed of fi red bricks and 

adobe. These sites are state historic landmarks. 

Although nothing is left of the original structures, 

the site of the original mission, Mission Vieja, is 

also a state landmark. Other remaining mission 

resources are located outside of the study area.

MEXICAN INDEPENDENCE AND THE RISE OF 

THE RANCHOS

Mexico gained independence from Spain in 1821 

and California fell under Mexican rule. Under the 

new government, missions became secularized, 

and land grants were given to individuals along 

with incentives to raise livestock. Many ranchos 

were established in the region. During this period, 

population growth in the region began to increase 

as overland routes to the West Coast were explored 

and established for trade and commerce. 

Photos (top to bottom): 1. Artist representation of 

the Juan De Anza Expedition - On the Trail by Bill 

Singleton, courtesy of NPS. 2. San Gabriel Mission. 

2006. NPS photo. 
58 Draft San Gabriel Watershed and Mountains Special Resource Study & Environmental Assessment 

Trade and Overland Routes (Westward 

Migration)

The Santa Fe Trail was the fi rst overland route to 

linking Missouri to Santa Fe, New Mexico. Later, 

trade routes linking Santa Fe further west to the 

Pacifi c were established. 

The Old Spanish Trail was the longest and most 

diffi cult pack mule route in America. The trail linked 

Mexican settlements in southern California with 

those in northern New Mexico. In 1829, Mexican 

trader Antonio Armijo succeeded in establishing a 

route from Abiquiu, New Mexico, to Los Angeles. 

The trail was used for trading woolen blankets from 

New Mexico for California horses and mules (Hafen 

1954).

Trade along the Old Spanish Trail tied into and 

contributed to a broader economic system, 

including the Santa Fe Trail/Chihuahua Trail trade, 

the Camino Real, and the ranching and maritime 

trade economy of California. Each area contributed 

its own resources to the trade. New Mexico 

supplied woolen goods to California and other 

markets. Within the study area, the ranchos were a 

signifi cant source for horses and mules. Mission San 

Gabriel was a supply point for early travelers and 

the destination for the fi rst trade caravan.

The Old Spanish National Historic Trail (NHT) was 

designated in 2002. A portion (21 miles) of the 

2,700 mile Old Spanish NHT passes through the 

study area from Claremont and going west to El 

Monte and into Los Angeles. Several areas within 

the study area represent settlements from the Old 

Spanish Trail. El Monte was an encampment. The 

state historic landmark plaque at the city’s Santa Fe 

Historical Park states that in the 1850s, some began 

to call El Monte “The End of the Santa Fe Trail.” 

The Bureau of Land Management and the National 

Park Service are producing a comprehensive 

management plan for the trail. 

Ranchos and Land Grants

In 1833, the Mexican government decreed the 

missions to be secularized, with their lands and 

properties dispersed (Thomas 1989). Many settlers 

and some Native Americans received land grants 

in the form of ranchos from the secularized lands. 

Ranchos occupied the valleys and foothills below 

the San Gabriel Mountains. The ranchos were 

primarily used for cattle grazing and agriculture. 

Southern California was heavily dependent on 

a pastoral economy. Cattle production became 

profi table since it required little labor and the lands 

were well suited for raising cattle. The demand for 

beef intensifi ed as the state’s population increased, 

mainly in the north, following the discovery of gold 

in 1848.

As cattle, sheep, horses and other livestock 

increasingly occupied the landscape many native 

plants lacked the adaptations to withstand the 

impacts of grazing and were soon replaced by 

invasive exotic plant species from the Mediterranean 

region. By 1860s, much of the native grasslands 

or California prairie had been displaced (Burcham 

1957; Schiffman 2005).

Ranchos continued into the early part of the 

American period until a series of winter storms and 

droughts beginning in the mid-1800s led to their 

collapse. According to the census, in 1860, there 

were 70,000 cattle in Los Angeles County; by 1870 

there were 20,000 cattle (Cleland 1941). During 

this period, sheep replaced the cattle. Raising sheep 

for wool production was an important industry in 

the valley from the 1860s through the 1870s. The 

collapse of ranching affected the economy in the 

region, greatly reducing the amount of funding 

from taxes to the state and county (Cleland 1941).

Ranchos within the Study Area

In 1837, the 22,000-acre Rancho San Jose became 

the fi rst former mission land to be granted. La Casa 

Primera de Rancho San Jose, built by the Palomares 

family in 1837, still stands in Pomona; it is now a 

museum and headquarters of the Pomona Valley 

Historical Society. The Casa de Madera, now known 

as the Palomares Adobe, also remains in Pomona 

and is open to the public. 

William Workman, John Rowland, and Juan Matias 

Sanchez, who arrived in California along the Old 

Spanish Trail, were granted Rancho La Puente 

and Rancho La Merced. In 1842, the 48,000-acre 

Rancho La Puente went to Rowland and Workman 

(Cleland and Dumke 1966; King 1990 and 1975). 

In 1850, Workman purchased Rancho La Merced. 

The 2,300-acre, triangular-shaped land grant was 

situated near the site of Mission Vieja. Workman 

later sold his half of Rancho La Merced to his ranch 

manager, Juan Matias Sanchez. The Sanchez Adobe 

still remains and is a historic site in the city of 

Montebello. 

Other ranchos with portions within or near the 

study area included:

 Rancho Santa Anita, owned by Hugo Reid, 

consisted of 8,000 acres. Reid was married 

to a Tongva woman, one of the few Indians 

who received land after secularization. Reid’s 

account of the Tongva is one of the few sources 

of information on Tongva life during this period. 
Chapter 2: Resource Description Cultural Resources 59

 Rancho Potrero Chico, owned by Juan Matias 

Sanchez, was one of the San Gabriel Mission’s 

original ranchos.

 Rancho Noghales (Los Nogales) included 4,000 

acres south of San Jose Creek.

 Rancho Azusa, named for the Indian Rancheria 

of Asuksangna, was granted to Andreas Duarte 

and Luis Arenas in 1841. 

• Rancho Paso de Bartolo Viejo was owned 

by Don Pio Pico, the last Mexican governor 

of California, who later became a rancher 

and businessman after American acquisition 

of California. Pio Pico State Historic Park in 

Whittier includes Don Pio Pico’s adobe mansion, 

and six acres of the former rancho.

 Other ranchos include Ex-Mission San 

Fernando, Rancho Tujunga, Rancho La Canada, 

and Rancho San Pascual (Hafen 1954; Robinson 

1991; King 1990). 

Rancho Period Resources

There are many resources from the Mexican Land 

Grant and Ranchos period that still remain within 

the study area. Many are listed on the National 

Register of Historic Places, the California Register, or 

are locally recognized historic sites. They include the 

Adobe De Palomares, La Casa Primero de Rancho 

San Jose, the Workman Adobe, the Workman 

Family Cemetery (El Campo Santo), the Rowland 

Adobe, John Rowland House, a mill on the San 

Gabriel River built by Rowland, and the Juan Matias 

Sanchez Adobe. Several sites associated with 

Rancho La Puente are listed on the National Register 

of Historic Places.

Mexican Period Impacts on Native 

Americans

Following secularization, most Native Americans 

left the missions to work on ranchos or to return to 

their native lands. Further spread of disease along 

with Spanish, Mexican, and American settlement in 

the state reduced the Native American population 

to approximately 125,000-150,000 (Cook 1978).
60 Draft San Gabriel Watershed and Mountains Special Resource Study & Environmental Assessment 

American / Contemporary Period

Prior to the U.S.-Mexican War of 1846-1848, the 

United States, inspired by the doctrine of “Manifest 

Destiny,” continued to expand to the west while 

Mexico struggled to control the lands acquired 

from Spain. During the war, Governor Pio Pico 

and General Castro concentrated their forces in 

the Los Angeles area. William Workman and John 

Rowland were some of the leaders of the American 

contingent (Hafen 1954). In January 1847, Mexican 

forces surrendered to the Americans in California, 

and in September, Mexico City fell, thus ending the 

war. In 1848, the Treaty of Guadalupe Hidalgo gave 

California to the United States (King 1990). The 

Rio San Gabriel Battlefi eld in Montebello is a state 

historic landmark commemorating the 1847 battle 

between American forces and Mexican Californians.

During the mid-1800s, southern California 

remained primarily Hispanic-dominated with a 

small population relative to northern California. As 

previously described, there was a brief explosion 

of wealth during the fi rst decade of the American 

period, as the Mexican rancheros provided beef 

for the gold miners in the mountain regions to the 

north. Signifi cant growth did not occur in southern 

California until the 1880s, with the arrival of the 

railroad and the fi rst real estate booms. These 

events brought profound changes to the social 

and cultural make-up of the region, with AngloAmericans replacing Hispanic Californians as the 

dominant group (National Park Service 2010). 

EARLY AMERICAN PERIOD IMPACTS ON NATIVE 

AMERICANS 

By the time the fi rst Americans settled in the Los 

Angeles area, Tongva survivors were scattered and 

working at a subsistence level on Mexican land 

grants. The discovery of gold in California brought 

numerous immigrants into regions, including the 

remote valleys of the Sierra Nevada, that had not 

previously been occupied by Euro-Americans. 

During 1845-1855, the Native American population 

was reduced from 150,000 to just 50,000. Between 

1770 (fi rst encounter with Europeans) and 1900, 

Native American populations severely declined from 

an estimated 310,000 to approximately 20,000 (a 

decline of over 90 percent) (Cook 1978). Today, it 

is estimated that a few hundred to a few thousand 

Tongva still live in California.

American Period Themes

During the early American period (1846-1950) 

the Los Angeles region experienced growth 

and advancements in commerce and industry, 

transportation, technology and engineering, arts, 

social history, recreation, and government. These 

themes and related resources in the study area are 

described below.

Commerce and Industry

The region’s resources provided opportunities for 

immigrants that moved to the region. Many settlers 

who came during the gold rush became involved in 

agriculture. Later, other industries and technologies 

such as road and water systems provided additional 

opportunities for the region to develop.

GOLD MINING

Throughout the late 1800s and early 1900s, mining 

contributed to the growth of the state. Although 

most of the new immigrants came to northern 

California, gold mining also contributed to the 

economy of southern California as the region 

provided food and supplies to the northern mines 

(Robinson 1973).

Some prospectors, however, did settle in the 

southern region with the hopes of discovering 

gold. Placer gold was mined in the San Gabriel 

Mountains as early as 1834. (See the Natural 

Resources “Mineral Resources” section). Gold 

had been discovered as early as 1842 in Placerita 

Canyon by Francisco López. This discovery may 

have contributed indirectly to the more famous, 

and consequential, American discovery in 1948 

by drawing attention to the potential for valuable 

mineral resources in the new state. This location lies 

just west of the study area. 

Mining was extensive, but few made any profi t in 

the region (Robinson 2007, pers. com.). The areas 

that were mined within the study area include the 

San Gabriel Canyon, Tujunga Canyon, the east 

slope of Mount San Antonio (Mount Baldy), and 

Mount Gleason (Clark 1998). The most productive 

gold mines were in the Acton District. The Governor 

and the Red Rover mines accounted for more 

than three-fourths of the total gold production in 

Los Angeles County since 1880 (Robinson 1973). 

Governor Mine was the most productive gold mine 

in Los Angeles County. The Bureau of Mines listed 

the total gold output of the Governor Mine as more 

than $1,500,000 – almost three times the yield of 

any other gold mine in the county. Red Rover had a 

total yield of $550,000 (Robinson 1973).
Chapter 2: Resource Description American Period Themes 61

The mining town of Eldoradoville, located at the 

main fork of the San Gabriel River, had a population 

of about 1,500 by 1861. Eldoradoville had general 

stores, dance halls, and several saloons. Miners had 

also set up camps along the East Fork of the river 

building wooden shacks and stone cabins (Smith 

1936).

Floods during 1859 and 1861 were diffi cult for 

mining operations on the San Gabriel. In 1868, 

nearly all of the mining equipment was swept out 

of the canyon. Eldoradoville was completely washed 

away in the winter of 1861-62, the same event 

which signaled the demise of southern California’s 

Hispanic cattle industry (Thrall 1935).

The enduring infl uence of gold mining can be seen 

today as gold-panning enthusiasts continue to take 

their pans out to the creeks, rivers, and streams of 

the San Gabriel Mountains. 

Mining-related resources

Former gold mining boomtowns, such as 

Eldoradoville, and other mining sites are located 

within the Angeles National Forest. The U.S. 

Forest Service is evaluating the Eldoradoville site 

for potential listing on the National Register of 

Historic Places. Gillibrand Claim #10 (Iron Blossom 

Mine), Vincent’s Blue Cat Claim, and Mining Site 

have been determined eligible for listing on the 

National Register of Historic Places. Other mining 

sites, including North Chilao Placer, Baldora 

Mining Complex, Noverto Placer Mine, Gold Bar/

Eldoradoville/Hooverville area, Steamshovel Placer, 

East Fork Old Miners’ Trail, and Bighorn Mine, are 

also being evaluated.

The Baldora Mine Complex appears eligible for the 

National Register. The preserved ball mill (Baldora 

Ball Mill No. 2) represents the most intact, complete 

mine of its type in California. The mines, mills, and 

their support buildings represent early 1900s mining 

technology in the San Gabriel Mountains and an 

important period of early exploration, settlement, 

and economic development of the region (Conkling 

and Sturm 1997).

Signifi cant sites related to the discovery of gold 

are also located just beyond the study area. 

Oak of the Golden Dream in Newhall is a state 

historic landmark commemorating California’s fi rst 

authenticated gold discovery by Francisco López.

PETROLEUM

Oil has long been an important resource in the 

region throughout history. Before the arrival of 

the Spanish, Native Americans used naturally 

occurring asphaltum for tools and craft works. 

Spanish and Mexican settlers learned to use pitch 

and coal tar from Native Americans. In the 1920s, 

oil was discovered near Newhall, in northern Los 

Angeles County (not far from Francisco López’s 

original gold discovery). Soon, more oil was found 

throughout the Los Angeles basin and in other parts 

of California. It soon became the most profi table 

industry in southern California. Oil production 

in California is ten times greater than its gold 

production and ranks 2nd in the nation among oilproducing states.

California’s petroleum industry began in the Santa 

Clarita Valley. The Pico Well No. 4, Pico Canyon 

Oil Field, west of Newhall (just outside the study 

area), was the fi rst commercially successful well in 

California and led to other oil production operations 

within the study area. Well No. 4 made Pico Canyon 

oil fi eld the most commercially successful oil fi eld 

in the entire west coast (Stein 1960; Western Oil 

and Gas Association 1965). It was also the longest 

continually operating oil well in the world. Oil 

production continued for 114 years before it was 

fi nally capped in 1990. The Pico Well No. 4, Pico 

Canyon Oil Field, is a National Historic Landmark 

District.

Within the study area, the Puente Hills and the cities 

of Whittier and Brea were also rich with oil. Oil was 

discovered in the Puente Hills in 1884 when William 

Rowland discovered oil on his father’s former ranch, 

Rancho La Puente. Rowland founded the Puente Oil 

Company, which produced over a million and a half 

barrels of oil in its fi rst 15 years (Keating 2006). 

Petroleum-related resources 

Olinda, located in Brea, was a boomtown in the 

late 1800s which supplied oil to the Santa Fe 

Railroad. The 2,300-acre Brea-Olinda fi eld produced 

more than 300 million barrels of oil in its lifetime 

(Keating 2006). The area stretched southeast from 

the Puente Hills through Brea and Tonner canyons 

to the site of old Olinda. Olinda Oil Well #1, drilled 

in 1897, is still pumping. Many structures tied to 

the oil industry have been removed, but features 

such as access roads, well pads, and several towers 

and pumps remain. The Brea Cañon Oil Company 

Building also remains. Olinda is a State Historic 

Landmark and is known as the Olinda Museum and 

Trail. 

AGRICULTURE

Agriculture played a signifi cant role in the 

development of the San Gabriel Valley. During the 

Spanish and Mexican periods, the missions and 

ranchos cultivated the land for crops and vineyards 
62 Draft San Gabriel Watershed and Mountains Special Resource Study & Environmental Assessment 

and grazed cattle and raised sheep. Agriculturalists 

fi rst had to overcome high costs for developing 

irrigation systems, a lack of local markets, limited 

transportation facilities, and fi nancial dependence 

upon bankers (Cleland 1941).

The completion of a transcontinental railroad to 

southern California in 1883 provided a means to 

distribute produce. With new advances in irrigation 

systems and the formation of water districts 

throughout the region, the fertile valleys and 

foothills were quickly converted to orchards and 

farms (Burcham 1957).

Citrus

The San Gabriel Valley and other parts of southern 

California were once dominated by citrus orchards. 

Citrus was fi rst planted by the Spanish missionaries 

in the early 1800s. Rancho landowners also planted 

commercial citrus orchards on their lands. By the 

late 1800s, citrus became very profi table in the 

region. 

In 1880, there were over 1.25 million citrus trees in 

southern California (Atchison, Topeka, and Santa 

Fe Railway 1938; Dumke 1944). In the 1880s and 

1890s, sheep herders of the San Gabriel Valley 

began to trade their stock to grow oranges. The 

California Foothill Orange and Lemon District 

stretched along the foothills from Pasadena to 

Claremont and into San Bernardino County. The 

southern region of the valley, including towns such 

as El Monte and Downy, grew citrus and row crops 

(McBane and Hartig 1998). The Pomona Valley area 

produced over $2 billion in revenues from the citrus 

industry between 1890 and 1940. 

In the mid-1930s, there were approximately 18,000 

growers and the citrus industry employed about 

200,000 people (Atchison, Topeka, and Santa Fe 

Railway 1938). The rapid growth of this industry 

had signifi cant impacts on workers in the region. 

Labor for the citrus industry was dominated by 

Mexican immigrants. This was aided by the removal 

of immigration restrictions for Mexicans in the early 

1900s. “By 1926, 10,000 Mexican pickers worked 

in Southern California citrus groves, and by 1940 

approximately 22,000 Mexican men labored in 

the orchards, constituting nearly 100 percent of 

the picking force. Approximately 11,000 Mexican 

women packed citrus fruit” (Garcia 2001).

Citrus-related resources. Resources from the citrus 

industry include structures such as packing houses 

as well as orchards. The College Heights Lemon 

Packing House/Claremont Packing House and 

the Teague Grove in San Dimas are examples of 

resources within the study area. The Teague Grove 

was one of the largest groves in the world. At one 

time it had nearly 250,000 trees. Today, there are 

about a dozen remaining trees.

Walnut

The walnut industry, like the citrus industry, thrived 

in the region. In the early 1900s, state production 

was almost entirely from southern California. The 

walnut crop was handled by brokers, speculators, 

and commission men. It suffered from poor 

marketing just as the citrus industry had. There 

were several local cooperatives, but at fi rst they did 

not take collective action. A central organization 

called the Executive Committee of Southern 

California Walnut Associations was formed in 1905. 

Later, the California Walnut Growers Association 

established grading standards. The Diamond Brand 

was known for having the best walnuts (Teague 

1944).

The Paradox Hybrid Walnut Tree in Whittier 

represents the once fl ourishing walnut industry 

in Southern California. The Paradox Hybrid was 

planted by the University of California Experiment 

Station in 1907. The university planted a dozen 

experimental walnut varieties. The Paradox Hybrid 

was the only one spared when the university gave 

up their lease in 1925 (Pomeroy 2000). 

Other crops

In addition to citrus and walnuts, other crops 

were also planted in the valley. Olives, fl ax, wheat, 

barley, oats, tobacco, alfalfa, silk, and cotton were 

examples of other crops grown. Many new crops 

were also grown for experimentation (Cleland 

1941, Dumke 1944).

Agriculture in the Antelope Valley

Agriculture fi rst peaked in the Antelope Valley area 

in the 1880s. With the arrival of the railroad, the 

formerly isolated Antelope Valley on the north side 

of the San Gabriel Mountains began to see its fi rst 

settlers. The fi rst homesteads in Antelope Valley were 

established where water was available. In 1886, 

Palmenthal was founded by Swiss German families. 

Its name was later changed to Palmdale. During 

the 1880s and early 1890s, heavy rainfall allowed 

homesteaders to successfully cultivate alfalfa, barley, 

wheat, and a variety of fruits and nuts. However, a 

serious drought between 1894 and 1904 devastated 

many farms, forcing some settlers to abandon their 

land. A second agricultural boom began in 1905 with 

the introduction of new irrigation techniques which 

provided the means for the large-scale cultivation 

of alfalfa. By 1920, alfalfa was the Antelope Valley’s 

major crop (Los Angeles County Libraries 2006).
Chapter 2: Resource Description American Period Themes 63

Early American Settlements in the 

Study Area

During the early part of the American period, 

many Mexican land grant holders held on to their 

grants until the 1870s or later. The California Land 

Act of 1851 addressed questions regarding preexisting property rights in California prior to United 

States acquisition of California. The act required all 

persons claiming lands in California to give legal 

proof of their claim in order to receive property 

rights under United States statutes (Raab 2005). 

After the collapse of the Hispanic ranching industry 

after the mid-1860s, landowners became interested 

in subdividing and developing their lands for other 

purposes.

The population of Los Angeles grew steadily from 

about 1,600 to 11,000 during the fi rst three 

decades of the American period. Settlements 

throughout the region were established following 

the arrival of the Southern Pacifi c Railroad in 

1876, success from industries, such as mining and 

commercial agriculture, and the land boom of 

the 1880s. During the land boom’s peak period 

in 1887, $100,000,000 worth of real estate in 

southern California was sold, more than 130,000 

persons remained as permanent settlers, and Los 

Angeles increased in size 500 percent (Dumke 

1944). Many people who came were only interested 

in realty speculation, but others were interested in 

settling and developing the area’s resources. This 

resulted in the development of many small towns 

while other town sites remained undeveloped with 

only staked-out lots (Dumke 1944). 

Photos (top to bottom): 1. Glendora orchards, San 

Gabriel Valley, 1931. Photo courtesy of Fairchild 

Aerial Surveys, Inc. and the Los Angeles County 

Library. 2. Pio Pico Adobe, 1919. Los Angeles County 

Library photo. 3. Workman House. 2007. NPS photo. 
64 Draft San Gabriel Watershed and Mountains Special Resource Study & Environmental Assessment 

Recreation

CONSERVATION, WILDERNESS AND MOUNTAIN 

RECREATION

In southern California, the arrival of the railway 

in 1876, followed by the boom of the agricultural 

industry started to place signifi cant pressures on the 

regional landscape. Furthermore, increased timber, 

hunting and fi shing, and devastating fi res in the 

region all took a noticeable toll on mountain areas 

and wildlife. As the landscape changed at a rapid 

rate in the late 1800s, many residents recognized 

the need to protect areas for recreation.

An interest in the wilderness and outdoors was 

furthered by the writings of naturalist John Muir. 

Muir fi rst hiked the San Gabriel Mountains in 1875 

where he reveled in the wildlife views, trails, and 

canyons that the mountains provided. In his book, 

“The Mountains of California,” Muir describes the 

waterfalls of the San Gabriel’s Eaton Canyon as 

a “charming little thing, with a low sweet voice, 

singing like a bird (Muir 1894).”

The alarming depletion of wilderness on both 

a national and local scale began to concern the 

American public. This eventually led to one of the 

nation’s most infl uential acts regarding land policy, 

the Forest Reserve Act of 1891. The Act provided 

Congress authority to set aside public lands for 

present and future use. Local residents mobilized to 

seek designation of both the San Bernardino and 

San Gabriel Mountain ranges as forest reserves. 

In 1891, the Los Angeles Chamber of Commerce 

appealed to Congress to have “all public domain 

included in the watersheds of Los Angeles, San 

Gabriel and other rivers in the Sierra Range” 

withdrawal from sale such that the mountains “may 

in future time serve the general public as a great 

park” (Robinson 1991). The San Gabriel Timberland 

Reserve, which is now in part the Angeles National 

Forest, was proclaimed by President Harrison on 

December 20, 1892, and was the fi rst forest reserve 

to be created in California and only the second in 

the United States. In 1905, legislation turned over 

reserve lands to the Department of Agriculture 

– later coming under management by the newly 

formed U.S. Forest Service. 

GREAT HIKING ERA

Hiking became a popular recreation activity in the 

late 1800s. The San Gabriel Mountains provided 

numerous trails through scenic mountain passages 

and became a prime destination for many outdoor 

enthusiasts. Many trails connected foothill 

communities to the mountains. For example, the 

Mount Wilson Trail, constructed by rancho owner 

Benjamin Wilson, begins in Sierra Madre. Later, the 

Pacifi c Electric Railway expanded rail lines within 

easy walking distances of mountain trailheads. 

With improved access, the San Gabriel Mountains 

became a weekend destination for many southern 

California residents. 

For nearly four decades (1890s-1938), hiking 

was tremendously popular among area residents. 

On a single holiday weekend, as many as fi ve 

thousand hikers passed through Joe Clark’s Half 

Way House, a check point on the Sturtevant hiking 

trail (Robinson 1946). Many accommodations 

for weekend travelers emerged near train depots 

and trailheads, including cafes, stores, and tourist 

camps. The Angeles National Forest was so popular 

that visitation between 1932 and 1933 alone was 

greater than visitation to all of the national parks 

at that time combined (Thrall 1934). During World 

War II, hiking popularity declined only to reemerge 

again during the post war boom. Today, the 

Angeles National Forest remains one of the most 

visited national forests in the United States. 

MOUNTAIN CAMPS, RESORTS, AND OTHER 

FACILITIES

Camps

As the San Gabriel Mountains became an 

increasingly popular recreation destination, tourist 

camps were developed to accommodate hikers. The 

fi rst of these camps, Switzer Camp, was established 

in the heart of San Gabriel’s Arroyo Seco in 1884. 

Rustic in nature, the camp consisted of tents, a 

communal log cabin, and a series of campfi re pits.

Throughout the 1880s and 1890s, Switzer Camp 

accommodated hundreds of guests from Southern 

California and inspired a wave of camp resorts 

throughout the San Gabriels, including Steil’s Camp, 

Dell’s Camp, Sturtevant Camp, Strain’s Camp, and 

Martin’s Camp. The popularity of these camps 

was so great that, in the summer of 1890, it was 

estimated that 1,000 people visited Steil’s camp in 

one summer alone (Robinson 1991).

Of these camps, the famed Sturtevant Camp, 

founded by Wilbur M. Sturtevant in 1893, was the 

most frequented and adored. Located in a wooded 

grove near a stream of the Big Santa Anita Canyon, 

Sturtevant camp’s picturesque location quickly 

became a favorite among hikers and campers 

(Robinson 1991).

Resorts

Professor and inventor Thaddeus Lowe and 

engineer David Macpherson were successful 
Chapter 2: Resource Description American Period Themes 65

entrepreneurs of the area. To further the concept of 

the San Gabriel Mountains as a tourist destination, 

they developed a plan for a rail line that would 

ascend Rubio Canyon to the summit of Echo 

Mountain, where tourists would fi nd an elaborate 

series of resorts. (The Mount Lowe Railway is 

further described in the “Transportation” section).

From 1892 to 1894, three mountain resorts were 

constructed along the railway: The Rubio Pavilion 

within Rubio Canyon, The Chalet near the top of 

Echo Mountain’s ridge, and the impressive summit 

resort of The Echo Mountain House. Popularly 

known as the “White City,” the incline railway and 

Echo Mountain Resort Complex soon became a 

sensation throughout the country.

During the 41 years of operation, the “White City” 

under the ownership of Lowe and later Huntington, 

were reported to have accommodated more 

than three million people. But the White City and 

Mount Lowe railway could not survive a series of 

unfortunate, natural events including windstorms, 

fi res, and a fl ood, which not only obliterated 

the elaborate railway system, but virtually every 

structure as well (Robinson 1991).

CCC-built facilities

As the Great Depression years began to set in, 

investment in parks and recreation began to 

diminish. During this time, President Franklin D. 

Roosevelt established the Civilian Conservation 

Corps (CCC), in addition to numerous other social 

work programs, to help improve the economy. The 

CCC played a signifi cant role in constructing many 

recreational facilities around the country. 

The California Region of the Forest Service had 

prepared new designs for Forest Service buildings 

during the establishment of the CCC. With these 

designs they were able to receive awards for 

several CCC camps to work on the construction 

of recreational facilities. The fi rst CCC camp in 

the country was reportedly built at Piru Canyon in 

the Castaic Range of the Angeles National Forest 

(Jones and Stokes 2004). Between 1933 and 1942, 

more than twenty CCC camps were established in 

the Angeles National Forest. With the assistance 

of other relief agencies such as the Work Projects 

Administration (WPA), the CCC were responsible 

for constructing many of the roads, campground 

facilities, and trails in the Angeles National Forest.

Other Recreation Facilities

The rise of the automobile had already brought 

a renewed interest to mountain resorts in the 

1920s. During this time, the Los Angeles County 

Board of Supervisors decided to construct a series 

of mountain recreational facilities in the San 

Gabriel Mountain’s Swarthout Valley. In 1923, 

construction began, with recreation buildings, 

trails, campgrounds, and picnic areas. At the center 

of these facilities was the Big Pines County Park 

– a fi rst-rate recreation facility envisioned by the 

Board. From roughly 1923-1933, the Los Angeles 

County Department of Parks and Recreation spent 

approximately four million dollars in developing the 

park. The park had a swimming pool, ice skating 

rink, tennis courts, children’s playground, numerous 

campgrounds, and ski and sled facilities (Robinson 

1991).

In the 1920s the Forest Service also began to 

develop campground facilities. Many of the facilities 

received supplemental funding from organizations 

including the Los Angeles Chamber of Commerce, 

the San Gabriel River Water Committee, and the 

State.

In the San Gabriel Mountains, the desire to 

drive to scenic destinations and recreation areas 

within the upper reaches of the mountains 

eventually outweighed the desire for hiking. Soon 

hiking camps began to close and were replaced 

with roadside amenities for tourists, including 

automobile convenience cabins. 

WINTER SPORTS

By the 1930s, winter sports were becoming a 

favorite pastime for southern California residents. 

Skiing, in particular, gained popularity. The 

mountainous locale of Big Pines Park proved to be 

an ideal location for the region’s fi rst ski resort. Big 

Pines soon became a popular skiing destination, 

hosting winter sports competitions in the mid1930s, attracting both local and world-class skiers. 

Though skiing and winter sports in general slumped 

in popularity during the depression and WWII years, 

ski resorts bounced back after the war (Robinson 

1991).

SPORTS CLUBS

Organized sports in the country and within 

southern California began to take hold at the 

turn of the 18th Century. In 1904, the town of 

San Gabriel founded the San Gabriel Country 

Club. Offering the fi rst 9-hole golf courses in the 

region, by 1912, the Country Club had signifi cant 

membership. The Country Club, still in existence, is 

considered the oldest golf club in both Los Angeles 

and Orange Counties. 

Nationwide organizations such as the YMCA and 

the Boy Scouts of America, which possessed strong 
66 Draft San Gabriel Watershed and Mountains Special Resource Study & Environmental Assessment 

recreational components, began to form local 

chapters in the San Gabriel Valley. The Boy Scouts 

of America opened its San Gabriel Chapter in 1910, 

and the West San Gabriel Valley YMCA chapter was 

established in 1912.

HISTORIC RECREATION RESOURCES

There are numerous historic resources within 

the study area related to recreation, including 

park areas, trails, and visitor facilities. Angeles 

National Forest resources under consideration for 

local and state recognition include: Crystal Lake, 

Charlton-Chilao, and Big Pines. Big Pines Park is in 

the process of being nominated for the National 

Register as a historic district. Within the study area, 

there are also fi ve Recreation Residence Tracts of 

cabins (Big Santa Anita, McClellan, Manker Flat, 

San Antonio Falls, and Upper San Antonio) all 

considered eligible for the National Register.

Resources that represent “The Great Hiking Era” 

include the Mount Wilson Trail and Lizzie’s Trail Inn 

/ Museum, which served hikers and packers as they 

headed up the Mt. Wilson trail starting in the early 

1900s. The Mount Lowe Railway is a designated 

National Register District listed at the state level of 

signifi cance. 

Transportation

As described earlier, the study area and the broader 

southern California region has a rich history of 

travel routes and transportation. Many migration 

and travel routes were determined by the regional 

environment, such as mountain passes and river 

corridors. Prior sections have already described 

Native American, Hispanic, and early American 

trade routes. This section describes the technology 

related to transportation, including railroads and 

the modern highway system.

RAILROADS

Railroads extended into the study area to meet 

the needs of the region’s growth during the mid1800s. The Southern Pacifi c Railroad and the Santa 

Fe Railroad were extended through the study 

area east from Los Angeles. When the Santa Fe 

offered competition in the mid-1880s, the rates 

were reduced, and the resulting rate war helped 

to increase migration to California. Along the San 

Gabriel Valley, the Santa Fe Railroad had stops at 

towns such as Sierra Madre, Arcadia, Monrovia, 

Duarte, Azusa, San Dimas, and Claremont (Dumke 

1944).

Several railroad stations/depots remain within 

the study area, including the Atchison, Topeka, 

and Santa Fe Railroad Station in Claremont, the 

Photos (top to bottom): 1. Electric car at Ye Alpine 

Tavern, Mount Lowe Railway, 1913. Shorpy.com 

photo. 2. Mexican Americans at San Gabriel River, 

1920. Photo courtesy of Shades of L.A. Collection 

and Los Angeles County Library. 3. Aztec Hotel, 

Route 66 (now Foothill Boulevard). 2006. NPS photo. 
Chapter 2: Resource Description American Period Themes 67

Southern Pacifi c Railroad Station in Whittier, and 

the Pomona Southern Pacifi c Railroad Depot.

Pacifi c Electric Railway

As towns in the region developed, they needed a 

connection to Los Angeles and to the main trunk 

railroad lines. The Pacifi c Electric Railway would 

provide that connection. Henry Huntington had 

envisioned building an interurban system that 

would cover Southern California (Crump 1962). 

The system began in 1873 when cars were pulled 

by horses and mules along iron railroad tracks. In 

1889, the Los Angeles Cable Railway Company 

began constructing a double track wire-cable 

railway. Pacifi c Electric was formed in 1911 by a 

merger of eight companies (Hilton and Due 1960). 

The Pacifi c Electric Railway was labeled by several 

transit historians as “The World’s Greatest 

Interurban Railway” (Fischler 1979). The railway was 

an exceptional example of an interurban system of 

its period. The Pacifi c Electric Railway spanned over 

1,000 miles of track and provided pollution-free 

transit in the Los Angeles region from hydroelectric 

power in the Sierra Nevada. 

The railway had a signifi cant impact on the 

development of the Los Angeles region. It 

encouraged new communities in the San Gabriel 

Valley by providing a link to Los Angeles. The 

railway also hauled freight and helped to improve 

transportation of citrus which was a primary source 

of income for the valley.

Historian William D. Middleton wrote “in a time 

before Southern California became the world’s 

most automobile-oriented society, almost everyone 

rode Pacifi c Electric’s ‘big red cars’ to the beaches, 

mountains, race tracks, and other pleasure spots 

of the Southland, as well as to and from their daily 

work” (Fischler 1979). The Pacifi c Electric Railway 

offered scenic vistas on lines which included the 

Mount Lowe Railway section, which climbed 3,130 

feet above Altadena in about 6 miles. Its last 

journey was in December, 1937. It is listed on the 

National Register of Historic Places. 

“Although some of the integrity of the Mount 

Lowe Railway has been affected over the years 

through fi re, fl oods, etc, much of the right-of-way 

and structures are still intact, and have become 

interpretive hiking trails” (Darrell Vance, personal 

communication, 2007).

In the 1920s, buses and cars started to compete 

with the Pacifi c Electric Railway. Highways and cars 

crossed rail lines and trolleys were slowed. The 

system did not keep up with technology. There 

were plans to build an underground network, but it 

was never implemented. Ridership greatly declined 

in the 1950s and the last trains ran in 1961.

The railway has been noted as a civil engineering 

landmark of California. It was the fi rst mountain 

railroad in the world to be operated by electricity. 

Andrew Hallidae, who designed San Francisco’s 

cable car system, designed the cable winding 

machinery. The Circular Bridge was the fi rst bridge 

in the world designed for both a curve and an 

ascending grade.

A comprehensive survey of remaining resources 

of the railway system has not been completed. 

Although much of the railway system no longer 

exists, there are a few remaining resources within 

the study area, including the Mount Lowe Railway 

National Register District, the Puente Largo Bridge, 

and railway depots and substations. The Great 

Bridge (Puente Largo) took trains over the San 

Gabriel River. The Great Bridge was an impressive 

structure constructed with reinforced concrete. 

The Pacifi c Electric Railway Bridge, also known as 

the Irving Gill Bridge, in Torrance, is listed on the 

National Register. The La Habra depot is now a 

performing arts theater. The Whittier freight depot 

which was shared with the Southern Pacifi c Railroad 

is now a transit center and the Whittier depot 

storefront ticket agency is now the Moose Hall. 

The Pacifi c Electric Railway Substation #8 nearby 

in Altadena is listed on the National Register of 

Historic Places.

Parts of the system, including trolley cars, can be 

seen in several museums including the Orange 

Empire Railway Museum in Perris, California. 

Existing rights-of-ways remain in portions of the 

study area. Many of the system’s rights-of-way 

were purchased by railroads and are preserved 

as rail transportation corridors. In 1990, the Blue 

Line portion of the Los Angeles County Metrorail 

System (outside the study area) opened. The line, 

for the most part, uses the Pacifi c Electric 4 track 

right-of-way. The Southern California Regional Rail 

Authority now operates Metrolink commuter trains 

on the former Covina-Claremont branch line.

HIGHWAYS

The popularity of automobiles changed 

transportation in the region and led to a departure 

from mass transit. Soon many roads through the 

study area were paved, including Route 66. Los 

Angeles County became the second largest auto 

manufacturing region in the nation in the mid1900s. Streets and highways were quickly built or 

modernized. Covina was one of the fi rst cities in the 

nation to pave all of its streets (King 1975). 
68 Draft San Gabriel Watershed and Mountains Special Resource Study & Environmental Assessment 

Route 66

U.S. Highway 66, popularly known as “Route 

66,” is the nation’s fi rst all-weather highway 

linking Chicago and Los Angeles. Route 66 was 

popular among thousands of motorists who drove 

west. The road, which opened in 1926, is 2,400 

miles long, although it is estimated that all of the 

various alignments total about 5,000 miles of 

roadway (National Park Service 1995). The study 

area includes 18 miles of Route 66 which crosses 

through the foothill communities and parallels, or in 

some areas is replaced by, Interstate 210.

Route 66 helped enable “the most comprehensive 

movement of people in the history of the United 

States” and linked the rural west to metropolitan 

areas. It provided an economic boom to the towns 

it passed through. Many businesses developed to 

serve the traveling public. The Route 66 corridor 

includes bridges motels, gas stations, diners, and 

other roadside businesses. Fanciful buildings, signs, 

and colossal sculptures were a colorful feature of 

highway culture and commerce during the 1920s 

and 30s. These “roadside attractions,” combined 

with natural features, create the distinctive 

character of the road (Cassity 2004). 

The congestion, safety issues, and need for 

an effi cient rapid transport system for defense 

purposes in post-war America during the 1950s and 

1960s, fi gured prominently in the passage of the 

Federal Aid Highway Act of 1956. This Act, which 

created the current Interstate system, led to the 

decline of Route 66 as a federal highway. The road 

was decommissioned in 1985.

Route 66 Corridor Resources within the Study Area. 

The portion of Route 66 within the study area is 

part of a high-growth urban metropolis. As a result, 

the area refl ects considerable change through time. 

In the early days of its history, the Route 66 corridor 

was dominated by citrus and other agriculture. Over 

time, the corridor has been extensively developed. 

Many buildings and signs remain that refl ect 

evolving periods of development (Kaisa Barthuli, 

personal communication, 2007). 

A National Park Service comprehensive survey of 

historic California Route 66 properties is underway. 

There are several resources identifi ed within the 

study area that are associated with Route 66 during 

its historic period:

The Aztec Hotel (Monrovia) 

The Azusa drive-in theater marquee (Azusa)

La Paloma Mexican Restaurant sign (La Verne)

Golden Spur Restaurant sign (Glendora)

Palm Tropics Motel (Glendora)

Colonial Motel (Azusa)

Stardust Motel (Azusa)

Other historic road features associated with Route 

66 will be identifi ed in the forthcoming survey 

(Kaisa Barthuli, personal communication, 2007).

Technology and Engineering

Engineering and technology played important 

roles in the history of the study area, including 

advancements in water systems, transportation, 

agriculture, and scientifi c discovery in space 

exploration and astronomy. This section describes 

the development of water supply and fl ood control 

systems in the region and the advances in scientifi c 

discovery in space exploration and astronomy.

Water supply 

The Los Angeles region is prone to periods of 

drought and massive fl oods. In the 1880s a legal 

battle over water in the region known as the 

“Battle of San Gabriel River” took place (King 

1975). The Wright Act was passed in 1887 and 

allowed cities to create water districts and develop 

irrigation. In 1889, a Compromise Agreement was 

made regarding what each town or region should 

receive from the river, and a permanent body, the 

Committee of Nine, was formed to settle any future 

disputes.

After years of drought, the city of Los Angeles 

pursued other means of bringing in other water 

sources. Ex-mayor Fred Eaton and city engineer 

William Mulholland (at the time in charge of the 

city Department of Water) traveled to the Owens 

Valley in 1904. Mulholland was convinced that an 

aqueduct could be built to carry water by gravity 

fl ow across the Mojave Desert and through the San 

Gabriel Mountains into the San Fernando Valley. A 

bond issue to purchase land and survey the route 

was passed in September 1905, and funding for 

the aqueduct was approved by voters in 1907. 

Construction of the Owens River aqueduct was 

completed in 1913 (Nelson 1983).

The construction of the aqueduct was highly 

controversial. The project took the water in the 

Owens River for the City of Los Angeles, leaving the 

former Owens Lake a dry alkali fl at. This generated 

much enmity among the agricultural community of 

the Owens Valley.

In the 1920s, Congress authorized construction of 

a dam at Boulder Canyon on the Colorado River. 

Construction of Hoover Dam began in 1931. The 

city of Los Angeles fi led an application with the 
Chapter 2: Resource Description American Period Themes 69

State Bureau of Water Rights to obtain water from 

the Colorado River after the completion of the dam. 

The 242-mile Colorado Aqueduct was a challenging 

engineering enterprise in its own right. Water had 

to be pumped out of Lake Havasu, the reservoir 

created behind Hoover Dam, and then over or 

through six mountain ranges (Nelson 1983).

A California Water Plan was approved in 1960 to 

address fl ooding issues, confl icts with northern and 

southern California, and to deal with the Supreme 

Court decision to reduce California’s share of 

Colorado River water by half. Later, the California 

Aqueduct was constructed, extending 444 miles 

along the west side of the San Joaquin Valley 

(Nelson 1983). A small portion of the aqueduct 

traverses the northernmost portion of the study 

area.

Flood control

As urban development increased in the 

early 1900s, the unpredictable nature of the 

meandering rivers of the Los Angeles basin was 

viewed as incompatible with the needs of the 

growing metropolitan region. Before the region 

was urbanized, fl ooding was considered an 

inconvenience, but it also benefi ted agriculture and 

ranching after periods of drought. With continued 

urban growth, however, natural fl ood events 

needed to be controlled. In addition, land use 

changes, including the construction of impermeable 

surfaces, altered the river systems and exacerbated 

the fl ooding. 

The fl ood of 1914, which caused $10,000,000 in 

damaged property, was the catalyst for the fi rst 

comprehensive effort to solve the fl ooding problem 

in Los Angeles (Bigger 1959). Before the 1914 

fl ood, fl ood control efforts were handled locally in 

a piecemeal manner. At the time there was no state 

or federal law that provided for comprehensive 

regional fl ood control. The Los Angeles County 

Board of Supervisors appointed a team of engineers 

to produce a comprehensive fl ood control plan for 

the county. The Los Angeles County Flood Control 

District was established as the central authority (Orsi 

2004). 

The fi rst plan consisted of dams in the mountains, 

check dams in the canyons, and the channelization 

of rivers in the Los Angeles Basin. Implementation 

of the 1915 Comprehensive Plan took several 

turns and ultimately resulted in mismanagement 

and a failed attempt at a large dam in San 

Gabriel Canyon. These events undermined public 

confi dence in the fl ood control authority. In 1931, 

under new leadership, the Flood Control District 

presented a new plan. This plan was similar to the 

1915 approach; however, it added the inclusion of 

Aerial view of fl ooding at Hall’s Canyon wash in La Canada, located in the Cresenta Valley between the San Gabriel 

Mountains and the Angeles National Forest. Spence Air Photo. Courtesy of the Los Angeles County Library.
70 Draft San Gabriel Watershed and Mountains Special Resource Study & Environmental Assessment 

spreading grounds to allow water to percolate into 

groundwater basins beneath the Los Angeles Basin 

(Orsi 2004). 

The 1936 Flood Control Act provided federal 

funding for comprehensive fl ood control projects. 

Because Los Angeles County already had a plan 

in place, the county was able to take advantage 

of this opportunity. This was the fi rst and largest 

program to receive funding under the new law. The 

1936 act and a subsequent fl ood control act passed 

in 1938 called for the Army Corps of Engineers to 

work with the Los Angeles County Flood Control 

District on future fl ood control efforts. This resulted 

in the Los Angeles County Flood Control System, 

a comprehensive, coordinated river-based fl oodcontrol system constructed by the Los Angeles 

County Flood Control District and the U.S. Army 

Corps of Engineers. 

Flood control structures were built by the 

Department of Public Works and the Army Corps 

of Engineers. Large dams were built, including the 

Devils Gate Dam on the Arroyo Seco in 1920. Early 

dams were built in mountain canyons, then further 

downstream on the rivers. Debris basins were 

constructed near the mouths of the canyons to 

collect erosion (Nelson 1983).

Five large dams were constructed on the San 

Gabriel River. The fi rst was Cogswell Dam in 1934. 

The other dams are Morris, San Gabriel, Santa 

Fe, and later Whittier Narrows in 1957. President 

Herbert Hoover attended the dedication of Morris 

Dam which played a part in the World War II effort. 

Morris Dam has been determined eligible for listing 

on the National Register of Historic Places. In total, 

14 dams were constructed.

In a theme study on large federal dams, the U.S. 

Bureau of Reclamation found that the Los Angeles 

County Flood Control System may be nationally 

signifi cant. Many of the system’s fl ood control 

resources are located within the study area. The 

theme study identifi ed potential contributing 

resources: dams, debris basins, spreading ground 

facilities, diversion tunnels, outlets, inlets, stilling 

basins, guide walls, gates, spillways, trash 

racks, penstocks, transformer yards, pumping 

stations, powerhouses, turbines, fi sh ladders, and 

temperature control devices (Billington, Jackson, 

and Melosi 2005).

Science. Scientifi c experiments and research have 

yielded valuable knowledge within the study area. 

For example, nationally signifi cant research has 

been conducted at the Mount Wilson Observatory 

and the San Dimas Experimental Forest for many 

years. 

Astronomy and astrophysics. Before the Mt. Wilson 

Observatory was constructed, the Mount Lowe 

Observatory on Echo Mountain was the principal 

astronomical institution in southern California. 

Constructed in 1894 by Thaddeus Lowe, builder of 

the Mount Lowe Railway, its director was Dr. Lewis 

Swift. There Swift discovered numerous nebulae 

and comets (National Park Service 1991).

The Mount Wilson Observatory was constructed 

in the Angeles National Forest, at the summit of 

100-inch telescope at the Mt. Wilson Observatory. 

June 1949. Photo reproduced by permission of The 

Huntington Library, San Marino, California. 

High fl ood water raging down the Puente Creek wrecks 

a Union Pacifi c train. 1927. Photo courtesy of the Los 

Angeles County Library. 
Chapter 2: Resource Description Other Cultural Themes Represented In The Study Area 71

Mount Wilson in 1904. Mount Wilson was chosen 

as the site for the observatory because of its 

location on a high mountain with clear skies (W.W. 

Robinson 1946). Later that year, the Mount Wilson 

Toll Road Company was formed to build a road to 

the site (Thrall 1937).

The Mount Wilson Observatory was a model 

modern facility that forever changed the history 

of the science of astronomy. The observatory 

contains fi ve signifi cant research telescopes that are 

still in operation: the Snow horizontal telescope, 

the 60-foot solar telescope, the 150-foot solar 

telescope, the 60-inch refl ector, and the 100-inch 

Hooker refl ector (National Park Service 1989).

At Mount Wilson, many well-known scientists, 

including Edwin P. Hubble and Albert Michelson, 

were able to make signifi cant astronomical 

discoveries and conducted many important 

experiments. For example, Nobel Prize-winning 

physicist Albert Michelson conducted an experiment 

to accurately measure the speed of light; he was 

also the fi rst to measure diameters of various stars.

Since 1986, the Mount Wilson Observatory has 

been operated by the Mount Wilson Institute 

(MWI), a non-profi t organization that focuses 

on scientifi c research, historic preservation, 

astronomical education, and public outreach. 

Several guest institutions operate facilities on the 

observatory.

A National Historical Landmark theme study for 

Astronomy and Astrophysics (1989) included a 

National Historic Landmark nomination for the 

Mount Wilson Observatory.

San Dimas Experimental Forest. The San Dimas 

Experimental Forest was established in 1933 

and is the only U.S. Forest Service experimental 

forest in southern California. The experimental 

forest maintains some of the earliest and most 

comprehensive records from continuously 

monitored experimental watersheds.

The experimental forest includes a range of facilities 

that were constructed through umemployment 

relief programs during the 1930s. The Lysimeter 

facility (tunnel and instrument room) is the 

largest of its kind in the world. It is a signifi cant 

engineering structure and is the most elaborate 

research facility on the experimental forest. The 

facility contains 26 large lysimeters (each measuring 

10.5 x 21 ft and 6 ft deep) and numerous small 

ones (Jones & Stokes 2004). 

An inventory and evaluation report for the 

experimental forest concluded that it appears 

eligible for listing on the National Register of 

Historic Places as a historic district. (Also see 

“Architecture” section in this chapter and the 

discussion in Chapter 3, Resource Signifi cance.

Other Cultural Themes 

Represented in the Study Area

Arts

ARCHITECTURE, 

LANDSCAPE ARCHITECTURE, 

URBAN DESIGN

There are numerous resources throughout the study 

area that represent diverse architectural styles, 

ranging from Mission/Spanish revival to Queen 

Anne. Types of structures and historic uses include 

adobes, hotels, and schools. Several structures are 

listed on the National Register of Historic Places 

for architecture – the Ygnacio Palomares Adobe 

(1854), located in Pamona, was the home of Don 

Ygnacio Palomares, one of the owners of Rancho 

San Jose; the Phillips Mansion (1875), also located 

in Pomona, is the only “Second Empire” style home 

in Southern California; the Temple Mansion, located 

in the City of Industry (original adobe home in 1842 

and remodeled in 1872 to resemble an English 

manor house); the Clarke Estate (1921) in the Santa 

Fe Springs is one of the best remaining examples of 

architect Irving Gill’s work.

Within the Angeles National Forest, the San Dimas 

Experimental Forest (SDEF) contains a signifi cant 

collection of Forest Service buildings and other 

structures constructed under Depression-Era relief 

programs. The SDEF fi eld headquarters located 

in Tanbark Flats is an excellent example of U.S. 

Forest Service architecture. Facilities at Tanbark 

Flat include a laboratory/offi ce, residences, a mess 

hall/ conference room, and several storage/utility 

buildings. Research/monitoring equipment includes 

rain gauges, stream gauges, debris dams, water 

quality samplers, a weather station, and a lysimeter 

complex. Other important CCC structures include 

stone landscape features that contribute to the 

cultural landscape (Jones & Stokes 2004).

The Glendora Bougainvillea, the largest growth of 

bougainvillea in the United States at 70 feet tall, 

represents landscape architecture. The two city 

blocks on which 24 individual bougainvillea plants 

grow, were once occupied by orange groves. The 

Glendora Bougainvillea, listed on the National 

Register of Historic Places, are some of the best 

remaining examples of the early twentieth century 

image of California as a paradise (Pomeroy 2000).
72 Draft San Gabriel Watershed and Mountains Special Resource Study & Environmental Assessment 

VISUAL AND PERFORMING ARTS

Several resources within the study area represent 

the performing arts, including the Pomona Fox 

Theater and the Padua Hills Theater in Claremont. 

In the early 1900s, Pomona and Claremont became 

prosperous from the citrus industry. The Pomona 

Fox Theater included state-of-the-art projection and 

sound systems and refrigeration air conditioning. 

The Padua Hills Theatre and the theatrical group, 

the Mexican Players, attracted thousands of visitors 

and provided education on the rich and diverse 

culture of Mexico (National Park Service 1998).

LITERATURE

The Upton Sinclair House, located in Monrovia, 

is a National Historic Landmark (NHL). The house 

represents Sinclair, who was one of the most 

infl uential American novelists focused on social 

justice in the early twentieth century.

Social History

CLUBS AND ORGANIZATIONS / REFORM 

MOVEMENTS

The La Puente Valley Woman’s Club, Montebello 

Woman’s Club, and Pomona YMCA Building are 

examples of clubs that represent social history 

within the study area. The Montebello Woman’s 

Club made substantial contributions to the city. 

They founded and staffed the fi rst library in 

Montebello, sold World War I bonds and stamps, 

and assisted the Red Cross in both World Wars 

(Pomeroy 2002). 

RELIGIOUS INSTITUTIONS

Several churches, temples, and other structures 

represent the religious diversity of the region. The 

Episcopal Church of the Ascension in Sierra Madre, 

founded in 1885, is constructed of stone modeled 

after churches of Sussex, England. The Hsi Lai 

Temple in Hacienda Heights is the largest Buddhist 

temple complex and monastery in the Western 

Hemisphere. 

Government, Military and Aerospace

Several resources within the study area represent 

government – both local government and federal 

government, including the U.S. Forest Service – and 

the United States military.

GOVERNMENT

There are many historic U.S. Forest Service buildings 

and facilities within the Angeles National Forest that 

are important in telling the history of the national 

forest. The West Fork Ranger Station, also known 

as “Old Shortcut,” was the fi rst ranger station 

built in California. The San Dimas Experimental 

Forest, as described earlier, includes buildings 

that are excellent examples of U.S. Forest Service 

architecture. Additional historic resources include 

recreation camps (Buckhorn, Messenger, Switzer), 

the Rincon administration site, trails, and fi re 

lookouts.

Within the San Gabriel Valley, Pio Pico Casa in 

Whittier, now part of Pio Pica State Park, represents 

Pio Pico, the last Mexican governor of California. 

Other structures are related to local government 

institutions. 

MILITARY AND AEROSPACE

During World War II, California played a major role 

in the war effort. There are several resources related 

to World War II and the Cold War that remain 

within the study area. The Morris Dam Test Facility 

in Azusa was used for military experiments to build 

an effective torpedo during World War II. The 

Navy conducted tests in the lake during 1942-44 

(John Robinson, personal communication, 2007). 

The Temporary Detention Camp for Japanese 

Americans at the Pomona Assembly Center and 

the Santa Anita Assembly Center (just beyond the 

study area) are two sites that are related to the 

internment of people of Japanese ancestry during 

World War II. These two assembly centers make 

up the Temporary Detention Camps for Japanese 

Americans State Historical Landmark. The Santa 

Anita Assembly Center was the largest assembly 

center. The Los Piñetos and the Mount Gleason 

Nike Installation sites in the Angeles National Forest 

Morris Dam. 2006. NPS photo. 
Chapter 2: Resource Description Cultural Landscapes 73

and two dismantled sites in the Puente Hills are 

from the Cold War era. Several post-World War II 

military plane crash sites (F-6 Hellcats and Lockhead 

T-33A) have been recorded in the Angeles National 

Forest.

During the 1950s, signifi cant technological 

advances were made with aviation. Within 

the study area and the region, numerous airtraining bases were established, where many 

aircraft manufacturers, including Douglas Aircraft 

and Hughes Aircraft, expanded or established 

factories. Antelope Valley was transformed from 

an agricultural area to a signifi cant place for the 

aerospace industry. The shift from agriculture to 

the aerospace and defense industry occurred in 

Palmdale during this period. Edwards Air Force 

Base (formerly Muroc Army Air Base) in Palmdale is 

the second largest base in the Air Force. In 1952, 

the U.S. government bought Palmdale Airport, 

renaming it Air Force Plant 42. Rockwell, Northrop, 

Lockheed, and McDonnell Douglas maintain 

production facilities at Plant 42.

The Space Flight Operations Facility (SFOF) in nearby 

Pasadena is a National Historic Landmark. The 

SFOF is signifi cant because it is the hub of the vast 

communications network through which NASA 

controls its unmanned spacecraft fl ying in deep 

space. The Mariner, Viking, Pioneer, and Voyager 

projects that have explored the solar system have 

all been controlled for at least part of their missions 

in this facility. The Jet Propulsion Laboratory has 

been the primary NASA center for the unmanned 

exploration of the planets.

Post World War II Period

World War II had a signifi cant impact on California 

and the study area region. Because of the war 

in the Pacifi c, the aircraft industry developed, as 

described earlier. The Los Angeles – Antelope 

Valley area were major production areas. “World 

War II gave California, along with the rest of the 

nation, an economic stimulus that swept the 

state to new pinnacles of prosperity, encouraged 

unbelievable population growth and a continuation 

and intensifi cation of the industrialization process 

which had started in the 1920s” (Cleland and 

Dumke1966). The Los Angeles Times noted in 1955 

that “The impact of the migration [into the Los 

Angeles area] averaging nearly 500 new residents a 

day for ten years, makes even seasoned statisticians 

sit up and take notice...Only fi ve American cities – 

New York, Chicago, Detroit, Philadelphia, and Los 

Angeles – exceeded the 1955 population of the San 

Gabriel Valley” (Cleland and Dumke1966). 

The period following the war was also one of 

substantial economic growth in the Los Angeles 

region. More than $1.6 billion was invested in 

industrial expansion during the postwar decade. By 

the mid-1950s Los Angeles was the third largest 

industrial and marketing center of the United States 

(Cleland and Dumke1966). Southern California 

diversifi ed its economic activities, expanding on 

the aircraft and oil industries, including automotive 

construction, metal products, food, and building 

materials. The downside to this growth was the 

impact on the environment, including smog. 

Despite extensive development of water resourced 

at the beginning of the century, as described above, 

water was still an issue for the region during the 

post-war era.

Cultural Landscapes

A cultural landscape is a geographic area including 

both cultural and natural resources, and wildlife or 

domestic animals therein associated with a historic 

event, activity, or person or exhibiting other cultural 

or aesthetic values. The study area includes several 

examples of cultural landscapes. 

Prehistoric Landscapes

Native American villages and seasonal camps 

were located throughout the study area. Many 

sites in the urban areas have been disturbed 

while other sites in the forest have been relatively 

well-preserved. As described in the archeological 

resources section, the Aliso – Arrastre Middle 

and North Special Interest Area is known to 

have numerous prehistoric archaeological sites. 

Sites range among long-term occupation sites, 

seasonal encampments and special-use resource 

procurement, processing, and storage sites. One 

site containing cupule rock art features is currently 

being nominated to the National Register of Historic 

Places (USFS 2005). A National Register nomination 

has been prepared for rock art sites within the 

forest dating from approximately 4000 to 200 B.P. 

(Whitley 2002). Because these archeological sites 

have not been disturbed by modern development, 

they retain exceptional potential for studying the 

cultures of native people and their relationship to 

the natural environment. 
74 Draft San Gabriel Watershed and Mountains Special Resource Study & Environmental Assessment 

Historic Landscapes

There are many cultural landscapes within the study 

area that represent themes such as transportation, 

recreation, agriculture, science, and architecture. 

Some cultural landscapes retain both historic and 

natural features while others do not. This section 

describes some examples of historic landscapes 

within the study area.

Beginning with the Hispanic Period, the Mission 

San Gabriel Arcangel retains some key structures. 

The church building began during the latter part 

of the 18th century and was completed in 1800; 

it remains in San Gabriel. Other extant structures 

include mills such as El Molino Viejo and another 

grist mill near the mission. Nothing remains of 

the original site of the mission, however. Other 

structures and natural features related to the 

mission landscape have been altered or removed, 

including elements related to ranching and 

agriculture.

Within the study area there are numerous historic 

resources that represent the ranchos, such as 

original homes; however, cultural landscape 

elements such as the spatial relationships between 

the remaining built environment and natural 

features are not readily evident. Landscape features 

usually associated with ranching operations and 

agriculture that would have surrounded these 

structures are no longer apparent since most 

of these areas have been developed or heavily 

urbanized. 

Even though many features of the Mount Lowe 

Railway within the Angeles Forest no longer remain, 

elements such as the natural setting, the path of 

the railway, and stone foundations and retaining 

walls of structures remain. Interpretive signs 

provide context for the railway, including spatial 

relationships among key features.

The San Dimas Experimental Forest contains 

cultural landscape elements that represent Forest 

Service administration and science. Structures that 

contribute to the cultural landscape were previously 

described under “Architecture, Landscape 

Architecture, Urban Design.” The natural landscape 

features of the experimental forest are intact. Many 

features have been preserved as the experimental 

forest continues to operate today.

Photos (top to bottom): 1. Mt. Lowe Railway, circle 

bridge view. 2007. NPS photo. 2. Mt. Lowe Railway 

track remains. 2007. NPS photo. 3. San Dimas 

Experimental Forest. Photo by the United States 

Forest Service. 
Chapter 2: Resource Description Cultural Landscapes 75

Resource Name Location Listing Status

SPANISH, MEXICAN, AND AMERICAN SETTLEMENT 

Juan Bautista de Anza National Historic Trail Extends through study area NHT

Old Spanish National Historic Trail Extends through study area NHT

Workman Adobe Industry NR-state

Hawkins--Nimocks Estate-Patricio Ontiveros Adobe Santa Fe Springs NR-state, SPHI

La Casa Alvarado Pomona NR-local

Jonathan Bailey House Whittier NR-local

Pitzer House Claremont NR-local

John Rowland House Industry NR-local

El Monte – 1st Southern Californian Settlement by 

Immigrants from United States

El Monte CR, SHL

Grave of George Caralambo Whittier SHL

Site of Mission Vieja Montebello SHL

J. D. Palomares Ranch La Verne SPHI

W. R. Rowland Adobe Redwood Ranch House Walnut SPHI

Juan Matias Sanchez Adobe Montebello SPHI, NRST3

NATIVE AMERICANS (Resources representing Tongva/Gabrielino, Tataviam, Fernandeno, and Serrano peoples)

Angeles National Forest Native American prehistoric 

resources determined eligible:

Alimony Earth Oven #2

Burial Site at Chilao Flats (also 51-33),

Chilao Creek Midden, 

House Pits at Lower Chilao

Lower Alder Creek Terrace Site

Old Shortcut Road Prehistoric Site #1

Angeles National Forest Determined eligible for 

NR

Additional resources in the study area:

Many archeological sites have been identifi ed 

but most have not yet been evaluated. Most 

numerous in Agua Dulce Quadrangle (33 sites)

Throughout study area 2 sites = NRST2

CLUBS AND ORGANIZATIONS

La Puente Valley Woman’s Club La Puente NR-local

Montebello Woman’s Club Montebello NR-local

Pomona YMCA Building Pomona NR-local

East Whittier Women’s Improvement Club Whittier SPHI

Women’s Club of Claremont Claremont SPHI, NRST3

Montebello Senior Citizens Center Montebello NRST2

Masonic Temple Pomona NRST3

RELIGIOUS INSTITUTIONS

Whittier First Christian Church Whittier NRST2

Rivera First Baptist Church Pico Rivera SPHI, NRST3

Claremont Missionary Home, Pilgrim Place Claremont NRST3

First Baptist Church Monrovia NRST3

First Methodist Episcopal Church, Seventh Day 

Adventist Church

Pomona NRST3

Table 3: Inventory of Cultural and Archeological Resources within the San Gabriel Watershed 

and Mountains Special Resource Study Area – Representation of National Park Service Themes
76 Draft San Gabriel Watershed and Mountains Special Resource Study & Environmental Assessment 

Resource Name Location Listing Status

German Baptist Church, Bible Missionary Church Santa Fe Springs NRST3

Holy Trinity Episcopal Covina NRST3

Methodist Episcopal Church, United Methodist 

Church

Monrovia NRST3

RECREATION

Old Short Cut, Chilao Visitor’s Center [West Fork 

Ranger Station] 

Angeles NF SHL, NRST2

Lizzies Trail End Museum/Lizzies Trail End Inn Sierra Madre SPHI, NRST3

Five Recreation Residence Tracts of cabins (Big Santa 

Anita, McClellan, Manker Flat, San Antonio Falls, and 

Upper San Antonio)

Angeles NF eligible for NR 

EDUCATION 

Barbara Greenwood Kindergarten Pomona NR-local

First Home of Pomona College (Ayre Cottage) Pomona SHL, NRST3

Reform School for Juvenile Offenders (Fred C. Nelles 

School)

Whittier SHL, NRST2

Bassett Elementary School Bassett SPHI

Soledad-Acton Schoolhouse Acton SPHI

Whittier Union High School Whittier NRST2

Duarte School, Duarte School Administration 

Building

Duarte NRST3

Claremont Colleges Claremont NRST5

Webb School of California Claremont NRST3

VISUAL AND PERFORMING ARTS

Padua Hills Theater Claremont NR-local, SPHI

Pomona Fox Theater Pomona NR-local

Mabel Shaw Bridges Music Auditorium Claremont NRST2

Lyric Theater, Crest Theater Monrovia NRST3

Mcnees, Bruens, Warner Bros Theaters, Whittier 

Theater

Whittier NRST3

LITERATURE

Upton Sinclair House Monrovia NHL

ARCHITECTURE, LANDSCAPE ARCHITECTURE, AND URBAN DESIGN

Clarke Estate Santa Fe Springs NR-state

Episcopal Church of the Ascension Sierra Madre NR-state

Glendora Bougainvillea Glendora NR-state, SHL

Workman Family Cemetery (El Campo Santo) Industry NR-state

Abraham Lincoln Elementary School Pomona SPHI

Atchison, Topeka and Santa Fe Railroad Station Claremont NR-local

Aztec Hotel Monrovia NR-local

Brea City Hall and Park Brea NR-local

DeWenter Mansion La Verne NR-local

Hoover Hotel Whittier NR-local

Ygnacio Palomares Adobe Pomona NR-local, SHL

John Carlton Pegler House Sierra Madre NR-local

Phillips Mansion Pomona NR-local, SPHI

Pitzer House Claremont NR-local
Chapter 2: Resource Description Cultural Landscapes 77

Resource Name Location Listing Status

La Casa Primera de Rancho San Jose Pomona NR-local

Lincoln Park Historic District Pomona NR- local

San Dimas Hotel San Dimas NR-local, SPHI

Scripps College for Women Claremont (within .5 mi of study 

area)

NR-local

Charles E. Straight House La Verne NR-local

Temple Mansion Industry NR-local

The Oaks Monrovia NR-local

La Casa de Carrión La Verne SHL, NRST3

Glendora Historic District Glendora NRST2

Leven Oaks Hotel Monrovia NRST3

12 individual listings for houses Whittier NRST3

36 individual listings for houses, 26 with no name Monrovia NRST3

28 individual listings for houses, 1 with no name Claremont NRST3

1 listing for a house Pico Rivera NRST3

1 listing for a house Sierra Madre NRST3

Pomona NRST5

Approximately 80 individual listings for houses and 

avenues or blocks in Claremont

Claremont NRST5

GOVERNMENT

Azusa Civic Center Azusa NR-local

Glendora District Offi ce Angeles NF Eligible (w/o 

concurrence)

Pio Pico Casa Whittier NR-state (NHL 

Evaluation in progress)

Vetter Peak Lookout Angeles NF NRST2

MILITARY

Pomona Assembly Center-Temporary Detention 

Camps

Pomona CR, SHL

Los Pinetos Nike Installation Angeles NF NRST2

Morris Dam Test Facility Angeles NF NRST2

Mount Gleason Nike Installation Angeles NF NRST2

Pomona Armory, National Guard Building Pomona NRST2

POLITICAL IDEAS, CULTURES, AND THEORIES

Site of Llano Del Rio Cooperative Colony Llano, on State Hwy 138 SHL

INDUSTRY (gold mining, petroleum, energy)

Edison Historic District Pomona NR-local

Orin Jordan House Whittier NR-local

Pitzer House

Standard Oil Building Whittier NR-local

Olinda Brea SHL

Pomona Water Powerplant Claremont SHL

Golden West Refi ning Company Santa Fe Springs NRST2

East Whittier Water Company Pumphouse Wittier NRST3
78 Draft San Gabriel Watershed and Mountains Special Resource Study & Environmental Assessment 

Resource Name Location Listing Status

AGRICULTURE

College Heights Lemon Packing House/Claremont 

Packing House

Claremont NRST2

Parent Haas Avocado Tree La Habra Heights NRST5

TRANSPORTATION

Route 66 Extends through study area NPS preservation 

program

Pomona City Stable Pomona NR-local

Southern Pacifi c Railroad Station Whittier NR-local

Lang (Southern Pacifi c: golden spike at Lang 

connected Los Angeles with San Francisco)

Santa Clarita SHL

Lyons Station Stage Coach Stop Santa Clarita (within .5 mi of study 

area)

SHL

Azusa Santa Fe Railroad Depot Azusa NRST2

Pomona Southern Pacifi c Railroad Depot Pomona NRST2

Santa Fe Railroad Depot Monrovia NRST3

Union Ice House, Ice House Claremont NRST3

Union Pacifi c Railroad Station Whittier NRST3

COMMERCE

National Bank of Whittier Building Whittier NR-local

National Bank of Pico Pico Rivera NRST2

Wells Fargo Bank Azusa NRST2

SCIENCE AND TECHNOLOGY 

Mount Wilson Observatory Angeles NF (NHL nomination 

prepared)

Paradox Hybrid Walnut Tree Whittier SHL

Mount Lowe Railway Altadena /Angeles NF NR district-state 

San Dimas Experimental Forest Angeles NF NR district (nomination 

prepared)

ENVIRONMENT

Angeles National Forest SHL

CHANGING ROLE OF THE UNITED STATES IN THE WORLD COMMUNITY

Juan Bautista de Anza National Historic Trail Extends through study area NHT

Old Spanish National Historic Trail Extends through study area NHT

Rio San Gabriel Battlefi eld Montebello SHL

OTHER RESOURCES: THEMES UNKNOWN

Captain William Banning Home Walnut SPHI

Old El Monte Jail El Monte SPHI

Richardson House Sierra Madre SPHI

Rosemead Historical Park Rosemead SPHI

Temple Hall – check if same as Temple Mansion Industry SPHI

The East Wing/Azusa Auditorium Azusa In CHRIS, not in NRIS

SR 30, Widen Baseline Road Claremont NRST2

no name (program reference # HUD880901H) Azusa NRST2

Baldwin Park City Hall Baldwin Park NRST2
Chapter 2: Resource Description Cultural Landscapes 79

Resource Name Location Listing Status

Central School Auditorium, Baldwin Park Civic 

Auditorium

Baldwin Park NRST3

Azusa Ioof Hall / Odd Fellows Building Azusa NRST2

Baughman House Claremont NRST2

Johnson Bros Ranch Claremont NRST2

Johnson House Claremont NRST2

Keeler Residence Claremont NRST2

W.K. Kellogg Arabian Horse Ranch Baldwin Park NRST2

2 sites with no name San Dimas NRST2

2 sites with no name La Puente NRST2

Covina Fire Station Covina NRST3

Orton Englehardt Historic Shop Building Glendora NRST5

Approximately 80 individual listings for homes and 

avenues or blocks in Claremont

Claremont NRST5

Sarah J. Abbott House Monrovia NRST5

Umbach House, Mildred Umbach Residence Monrovia NRST5

no name Monrovia NRST5

Sites that have potential for listing on the NR, CR, or local listing/designation:

There are 135 historical sites within the study area appear eligible for listing on the National Register, California 

Register, or other local listing as individual sites and contributors to a district. Most of these sites need survey evaluation

to determine eligibility. These are NRST 7N: Needs to be reevaluated (Formerly NR Status Code 4 – may become eligible 

for listing on the NR)

There are 106 sites that need to be reevaluated to determine whether they have potential for listing on the NR, CR, or 

local listing/designation.

Sources: 

 National Park Service, National Register of Historic Places Database

 Angeles National Forest, Heritage Resources Database

 State of California, Lists of State Historic Landmarks, Points of Historical Interest, Historic Resources Inventory database, Archeological Resources Determination of Eligibility Database

 County of Los Angeles, Department of Regional Planning, list of resources within the county including unincorporated lands

Notes:

 Data was compiled in 2007. Data is not comprehensive at the local level. Many cities have their individual local landmarks. This information has not been collected for every city/community within the study area.

 Although many resources represent more than one theme/topic, they are listed under their primary them/topic.

 Location information for archeological sites and historic sites on private land that have been determined eligible/or 

potentially eligible for listing on either the National Register of California Register is not identifi ed.

Status codes:

NHL = National Historic Landmark

NHT = National Historic Trail

NR = National Register

NRST2 = Determined eligible for listing on the National Register or California Register

NRST3 = Appears Eligible for NR as an individual property through survey evaluation

NRST5 = Eligible for local listing or designation

SHL = California State Historic Landmark

SPHI = California State Point of Historic Interest
80 Draft San Gabriel Watershed and Mountains Special Resource Study & Environmental Assessment 
Chapter 2: Resource Description Recreational Resources 81

Recreational Resources

Introduction

With its diverse landforms and landscapes, 

the study area features a variety of scenic and 

recreational resources. Large, wild, open spaces 

in the mountains and hills are contrasted with 

dense urban areas. Within the large expanse of 

urban areas, hidden “wild places” that provide 

recreational opportunities can be found. A short 

drive can take a person from one of America’s 

most densely populated regions, to stark desert 

and serene wilderness areas. Sub-alpine mountain 

environments are located just miles away from dry 

deserts and mild coastal beaches. 

Recreational resources in the study area range 

from the Angeles National Forest in the San 

Gabriel Mountains to small neighborhood parks. 

Recreational activities include: organized sports 

activities, recreational mining, spiritual gatherings, 

swimming, hiking, biking, swimming, camping, 

picnicking, fi shing, wildlife viewing, hang-gliding, 

use of off-road vehicles, and hunting. Despite the 

diversity of recreational opportunities and open 

spaces, the region has had diffi culties preserving 

enough open space and recreational areas to meet 

the needs of its ever growing population. 

This section describes an overview of recreational 

use in the study area, an inventory of recreational 

resources, an analysis of recreational needs and 

demand, and future opportunities for recreation 

within the study area. 

Inventory of Existing Parks and 

Open Space

OVERVIEW OF PARKS AND OPEN SPACE

The study area features a variety of areas devoted to 

recreation in some form, often in conjunction with 

the preservation of natural open space or historic 

sites. These include the federal, state, joint powers 

authority lands, and an assortment of regional and 

local parks, nature centers, and preserves. Parks and 

open space are not evenly distributed throughout 

the region, and access for those without private 

transportation is limited.

With the exception of the Puente Hills Landfi ll 

Native Habitat Preservation Authority Area, and 

two county regional parks, large open spaces in 

the more urbanized portions of the study area are 

relatively sparse, consisting of isolated patches or 

narrow, disconnected corridors of green space in a 

matrix of urban development. 

Open space may be described as any land that 

is not developed for urban use. This may include 

natural areas set aside for species protection, lands 

used for agriculture or natural resource extraction, 

recreational areas, or areas unsuitable for 

development either due to a potential hazard (such 

as slide areas or fl oodplains) or due to other uses 

such as groundwater recharge or fl ood protection 

(San Gabriel and Los Angeles Rivers and Mountains 

Conservancy 2001). 

Parks are a type of open space that is designed 

and managed for multiple uses such as recreation, 

natural resource conservation, and education. 

Table 4. Agencies Administering Parks and Open Space in the Study Area

Federal USDA Forest Service (USFS)

US Army Corps of Engineers (ACOE)

Bureau of Land Management

State San Gabriel and Lower Los Angeles Rivers& Mountains Conservancy (RMC)

Santa Monica Mountains Conservancy

California State Parks

Regional Park Districts Puente Hills Landfi ll Native Habitat Preservation Authority

Joint Powers Authorities (JPAs) Mountains, Recreation and Conservation Authority

Puente Hills Native Habitat Preservation Authority

Watershed Conservation Authority

County Los Angeles County Department of Parks & Recreation

Los Angeles County Department of Public Works

County of Orange Resources and Development Management Department / Harbors, Beaches and 

Parks Division

Districts School Districts

Cities City Parks and Recreation Departments, Community Services Departments
82 Draft San Gabriel Watershed and Mountains Special Resource Study & Environmental Assessment 
Chapter 2: Resource Description Recreational Resources 83

Recreational use may be designated active, passive, 

or both. Passive use refers to activities that are 

generally low impact such as hiking, fi shing, 

picnicking, bird watching, or non-motorized 

boating. Active recreational use may include 

facilities designed for sports such as soccer or 

baseball, lakes for motor-boats and jet skis, bicycle 

trails or equestrian trails. 

This section examines parks and open spaces 

that are specifi cally managed for recreation or 

conservation purposes as well as areas which are 

not exclusively managed for public recreation and 

conservation purposes but offer some recreational 

opportunities. The latter areas include country 

clubs, botanical gardens, schools and universities, 

and cemeteries.

Within the study area, agencies from all levels 

of government provide open space, park, and 

recreational amenities (See Table 4, Agencies 

Administering Open Space and Recreation in the 

Study Area.)

PARKS AND OPEN SPACE MANAGED FOR 

RECREATION AND CONSERVATION

The following section describes parks, open space 

and regional recreation areas that are specifi cally 

managed to provide recreational opportunities. A 

summary of these areas within the study area is 

provided in Table 5. Also, see Map: Parks and Open 

Space for an overview of distribution throughout 

the study area.

Local and Community Parks

Local and community parks are generally less 

than 50 acres and are designed to serve the 

active recreational needs of neighborhoods and 

communities. The types of parks that would fall 

in this category include tot-lots, athletic fi elds 

and courts, and playgrounds. Activities include 

play, organized sports, picnicking, barbequing, 

and hiking or walking on trails. Over 200 local 

and community parks are located in communities 

throughout the study area. Together these parks 

provide over 2,500 acres of land for managed 

specifi cally for recreation. These parks are typically 

managed by city park agencies and community 

services departments.

An analysis conducted by the Trust for Public Land 

demonstrated that higher density communities 

with lower than average median income in Los 

Angeles County typically do not have adequate 

access to local and community parks. While many 

cities in the study area have ample access to local 

and community parks, others have few or no 

Photos (top to bottom): 1. Santa Fe Dam Recreation 

Area. NPS photo. 2. Eaton Canyon Natural Area. NPS 

photo. 3. East Fork San Gabriel River. NPS photo. 
84 Draft San Gabriel Watershed and Mountains Special Resource Study & Environmental Assessment 

parks available. The section, Recreation Needs and 

Opportunities, discusses this issue further.

County and Regional Parks

The Los Angeles County Department of Parks and 

Recreation manages numerous parks throughout 

the study area. Some county parks function as local 

and community parks for unincorporated areas of 

Los Angeles County while others function as large 

regional parks that offer many types of recreation 

opportunities to a large service area. The County of 

Orange manages Craig Regional Park which spans 

the cities of Brea and Fullerton.

Major fl ood protection facilities in the Los 

Angeles Basin function as regional recreational 

areas. These include Whittier Narrows Recreation 

Area, Frank G. Bonelli Recreation Area, and 

Santa Fe Dam Recreational Area. Each of these 

regional parks provides over 1,000 acres of land 

for recreation. They afford a wide variety of 

recreational opportunities including trails and bike 

paths, boating, athletic fi elds, concession services, 

swimming, nature centers, camping (Frank G. 

Bonelli Regional Park only), fi shing, event venues 

(such as amphitheaters), and barbeque/picnic areas. 

Whittier Narrows and Santa Fe Dam Recreational 

Areas also have nature centers and natural areas. 

Walnut Creek County Park is a linear park that 

follows Walnut Creek from Frank G. Bonelli County 

Regional Park several miles west through San Dimas 

and Covina. 

Devil’s Punchbowl is a 1,300-acre regional park 

managed by Los Angeles County at the northern 

end of the study area. Adjacent to the Angeles 

National Forest and near the San Andreas fault, this 

park was set aside so that visitors could learn about 

and enjoy the dramatic sandstone formations. 

Devil’s Punchbowl features a nature center and 

miles of hiking trails. Wildlife viewing is another 

popular visitor activity at this park. 

The largest of the regional parks is the Puente Hills 

Landfi ll Habitat Preservation Authority Preserve 

(Preserve) which includes 3,860 acres of land in 

the Puente Hills. The Preserve was established in 

1994 and is managed by a joint powers authority 

with a Board of Directors represented by the City of 

Whittier, the County of Los Angeles, the Sanitation 

Districts of Los Angeles County, and the Hacienda 

Heights Improvement Association. Solid waste fees 

from the Puente Hills Landfi ll provide funding for 

the Preserve (Puente Hills Landfi ll Native Habitat 

Preservation Authority 2007). 

Golf Courses

Large and small golf courses are found throughout 

the study area. Although Los Angeles County 

Table 5: Approximate Acreage of Study Area Parks and Open Space

Parks and Open Space Units Approximate acreage within study area % of study area 

(707,000 acres)

Local and Community Parks 241 2,500 <1%

County and Regional Parks 35 11,050 1.6%

Golf Courses 20 1,650 public course (1300 private) <1%

Wilderness Parks 8 3,100 <1%

Historical Parks and Cultural Sites 3 115 <1%

Equestrian Parks (public) and Districts 7 535

<1%

Bureau of Land Management Lands (BLM) 28 3640

<1%

Angeles National Forest 1

415,000 (5,000 acres or 1.1% of the forest lands 

are considered developed recreation areas*)

59% 

Total Open Space (including forests and BLM lands) = 437,590 acres

Total Open Space (excluding national forest lands and BLM Lands that have not been developed for recreational access) = 23,950

acres

*Developed recreation areas in the Angeles National Forest include campgrounds, parking areas, day use areas, picnic areas, visitor 

centers, rest areas, lakes and reservoirs used for recreation, river access, and scenic overlooks. 

** Congressionally-designated Wilderness areas acreage is included in the total acreage for the Angeles National Forest

Sources: Green Visions Parks GIS Database (2006), Puente Hills Landfi ll Native Habitat Authority (2007), Protected Open Space Lands 

GIS Database (2005), USFS (2005), Southern California Association of Governments Land Use GIS Data (2001).
Chapter 2: Resource Description Recreational Resources 85

and several municipal governments manage golf 

courses for the general public, many golf courses 

in the study area are privately managed. Public golf 

courses also typically require usage fees. The study 

area features almost 3,000 acres of golf courses. 

More than half of these (1,650 acres) are available 

for the general public. Approximately 1,300 acres 

are part of private clubs where membership is 

required. Golf courses are typically land- and 

resource-intensive facilities. Golf courses in the 

study area are about 60 acres on average, although 

they range in size from a few small courses at 10-20 

acres to large 100-200-acre courses. 

Wilderness Parks

In recent years land conservancies and municipal 

governments have cooperated to preserve 

wilderness parks. Wilderness parks are large, 

undeveloped open spaces that provide passive 

recreational opportunities and protect habitat 

for wildlife. Recreational activities include hiking, 

biking, horse-riding and dog-walking. Wilderness 

parks are typically located in foothill communities 

such as Claremont, Glendora, Arcadia, La Verne, 

and Pasadena and provide connections to the 

Angeles National Forest. Galster Wilderness Park in 

West Covina is located in the San Jose Hills. Over 

3,100 acres of land in the study area has been 

designated as this type of parkland.

Pasadena manages a unique kind of natural 

park called a watershed park. The Hahamongna 

Watershed Park is located above Devil’s Gate Dam 

adjacent to the Angeles National Forest. Established 

in 1997, these lands were previously used for 

sand and gravel mining operations. When these 

operations ceased, habitat was restored and a park 

was established based on community input and 

participation. The park is meant to be a showcase 

for water and natural resources education and 

utilization, preservation of native plants and habitat, 

Native American culture, and both passive and 

active recreation. 

Historical Parks and Cultural Sites 

Often cultural and historic sites occur within a 

park-like setting and are managed by government 

agencies or non-profi t organizations. These facilities 

tend to have an educational mission, which provide 

opportunities for outreach and education. Only 

one state park is located within the study area, 

Pio Pico State Historical Park. Local historical 

parks, museums, and markers that commemorate 

historical events and features are found throughout 

the study area.

Equestrian Parks, Centers, and Districts

Use of trails and river corridors by equestrians has 

a long history in the study area. The horse also 

was the center of nearly all sporting events for 

the Spanish and Mexican settlers. Horse races, 

bullfi ghts, rooster pulls, rodeos (or charreadas), and 

a variety of other daring feats performed on horses 

demonstrated the level of one’s horsemanship while 

entertaining an enthusiastic audience (Welles 1972). 

This tradition continues today. The Pico Rivera 

Sports Arena near the San Gabriel River still hosts 

traditional charreadas.

Various equestrian facilities are located throughout 

the study area. Although many of these equestrian 

facilities are privately managed, the City of Industry 

and Glendora feature public equestrian parks. 

Equestrian facilities are also located in Pico Rivera at 

Bicentennial Park and Whittier Narrows 

Los Angeles County has designated equestrian 

districts in several places in the study area. 

Equestrian districts are established to recognize 

particular areas where the keeping or maintaining 

of horses and other large domestic animals for the 

personal use of members of the family residing on 

the premises has become, or is intended to become, 

an integral part of the character of the area (Los 

Angeles County Code, Title 22, Chapter 22.44, 

Part 3). Of the eight Equestrian Districts designated 

throughout Los Angeles County, fi ve are located in 

the study area. All fi ve of these areas are located in 

close proximity to Whittier Narrows, the San Gabriel 

River, and San Jose Creek.

BUREAU OF LAND MANAGEMENT LANDS

The Bureau of Land Management (BLM) manages 

over 3,000 acres of land in study area. These lands 

consist of isolated parcels scattered throughout 

Soledad Basin and the Antelope Valley. Lands in the 

Soledad Basin are managed by BLM’s South Coast 

District Resource Management Plan. This plan has 

designated most of the parcels in the study area 

for sale or exchange under Federal Land Policy and 

Management Act of 1976 (FLPMA). The FLMPA 

declared it the policy of the United States that “...

the public lands be retained in Federal ownership, 

unless as a result of the land use planning 

procedure provided in this Act, it is determined that 

disposal of a particular parcel will serve the national 

interest...” Several parcels are designated for 

exchange with the National Forest Service. Antelope 

Valley parcels are managed under the West Mojave 

Plan. These will be retained or consolidated to 

refl ect their value wildlife habitat and rare species 

(BLM 1994 and 2006). 
86 Draft San Gabriel Watershed and Mountains Special Resource Study & Environmental Assessment 

ANGELES NATIONAL FOREST 

Visitation and Use

Located in the heart of the greater Los Angeles 

metropolitan region, over 15 million people live 

within a 90-minute drive to the Angeles National 

Forest (ANF). Proximity to such a large urban 

population means that the ANF is one of the most 

visited national forests in the United States. In 1992, 

the U.S. Forest Service reported that the Angeles 

National Forest was the second highest ranked 

national forest in the United States for intensity 

of use. The Forest Service estimates that over 3.5 

million visitors come to the national forest on an 

annual basis, making recreation the predominant 

use of the forest. 

Comprising over 70% of Los Angeles County’s 

open space, the ANF primarily serves day-use 

and family recreation activities. Almost all of the 

visitors to the forest are local in origin. Because 

over 90% of the San Gabriel Mountains are steep 

and rugged, these visits tend to be concentrated 

in the developed recreation areas that are easily 

accessible by roads. Major destination areas include 

San Gabriel Canyon, Crystal Lake, Big and Little 

Tujunga Canyons, and the area surrounding Mt. 

Baldy. Summer visitation is heaviest along areas with 

water recreation such as the San Gabriel Canyon. 

Winter recreation is focused around the Mt. Baldy 

area with its developed ski resorts (USFS 2007). 

Primary visitor facilities within the study area include 

two visitor centers, campgrounds, ski areas, picnic 

areas, trails, and roads. There are several private 

camps and recreation areas that serve various 

organizations throughout the region. 

Waterfalls are an important recreational feature 

of the San Gabriel Mountains portion of the ANF. 

Geologic uplift associated with the Sierra Madre 

fault system created numerous falls that dot the 

southern base of the mountains. Some of the 

most popular and easily accessed falls include the 

Pasadena glen Falls, Monrovia Canyon Falls, Millard 

Canyon Falls, Lewis Falls, Bailey Canyon Falls, San 

Antonio Falls, Eaton Falls, Sturtevant Falls, and 

Switzer’s Falls (Chester 2004). 

Angeles National Forest lands in the San Gabriel 

Mountains are also heavily used by communities of 

faith. The mountains and the San Gabriel River are 

used for baptisms, retreats, faith hikes, pilgrimages, 

camping, and other spiritual activities such as 

prayer and meditation. There are about a dozen 

church camps in the San Gabriel Mountains, most 

notably Sturdevant Camp and the several Christianowned camps that border the Pleasant View Ridge 

Wilderness area. 

Visitor Services

Visitor services provided in the Angeles National 

Forest include interpretive services, visitor 

center management, interpretive media, inforest concessions, management, fee collection, 

community outreach, visitor safety, and law 

enforcement services. The overall mission of the 

interpretive services, visitor centers, and education 

program is to forge intellectual and emotional 

connections between people and their natural and 

cultural heritage. 

Community outreach includes activities that 

encourage the stewardship of national forest lands 

through the participation of people from local areas. 

These efforts lead to sustainable recreation within 

the national forest. Partnerships and volunteers are 

emphasized to improve visitor services and increase 

opportunities for interpretation and environmental 

education. 

The Angeles National Forest manages approximately 

500 recreation special-use authorizations, including 

four concession campground complexes, two 

concession target shooting areas, fi ve ski areas, 

a marina, 26 organization camps, and over 

450 summer homes. The forest also issues and 

administers numerous recreation events, such as 

mountain bike events and car rallies (USFS 2005). 

Facilities

The Angeles National Forest operates over 350 

buildings throughout the national forest. These 

range from restroom facilities and fi re stations 

to administrative offi ces. In addition, the forest 

operates 63 campgrounds with over 1,100 

individual campsites and an additional 36 picnic 

areas. Numerous trails are located on the forest; 

these trails are described in the following section, 

Trails and Scenic Highways.

Multiple agencies maintain a large road network 

in the national forest, including bridges, culverts, 

low-water crossings, and tunnels. The California 

Department of Transportation is responsible for 

three major highways: California State Route 2, 

California Interstate 5, and California State Route 

39. Los Angeles and San Bernardino Counties also 

maintain a portion of the network. The U.S. Forest 

Service maintains 1,000 miles of roads.

The 2005 Forest Plan indicates that roads and 

trails will be maintained to minimize the level 

of effects to species and watersheds while 

safely accommodating use. National Forest staff 

plan to maintain approximately 10 percent of 

National Forest System roads to their objective 
Chapter 2: Resource Description Recreational Resources 87
88 Draft San Gabriel Watershed and Mountains Special Resource Study & Environmental Assessment 

maintenance level. Decommissioning of unneeded 

or unauthorized roads and trails will be emphasized. 

ANF staff plan to complete site-specifi c road analysis 

on approximately 30 percent of the unclassifi ed 

roads and make appropriate designations.

Wilderness Areas

There are four Congressionally-designated 

wilderness areas in the study area, all of which 

are located in the Angeles National Forest. The 

San Gabriel Wilderness area is over 36,000 acres. 

It is located north and east of the West Fork of 

the San Gabriel River. It includes rugged terrain 

ranging in elevation from 1,600 to 8,200, most 

of which includes chaparral habitat. Higher 

elevations are dominated by fi r and pine forests. 

Popular recreation activities that occur in this area 

include hiking, fi shing, waterplay and picnicking. 

Most of this visitation occurs on trails and riparian 

woodlands located in canyon bottoms.

The Sheep Mountain Wilderness area is over 39,000 

acres and located on the eastern end of the San 

Gabriel Mountains. Approximately 400 acres of 

this area is located on the San Bernardino National 

Forest. Elevations range from 2,400 ft. to over 

10,000 ft. This highly scenic wilderness area is 

primarily chaparral habitat. Several pre-1964 mining 

operations are located in this area with special-use 

authorization (USFS 2005). 

In 2009, Congress designated two new wilderness 

areas in the Angeles National Forest, both of which 

are located in the study area. The Magic Mountain 

Wilderness area is over 12,000 acres; it features 

steep narrow canyons with a combination of 

chaparral, pines and hardwood forests. This area 

provides habitat for many of the forest’s threatened 

and endangered species. There are no offi cially 

designated trails that fall within this wilderness 

area. The Pleasant View Ridge Wilderness area, 

containing almost 27,000 acres is located in the 

northeastern section of the San Gabriel Mountains 

and includes the northern slope where the 

mountains meet the Mojave Desert. The area is 

known for its majestic peaks and spectacular views 

of the San Gabriel Mountains and desert basin. It is 

traversed by the Pacifi c Crest Trail. 

Trails and Scenic Highways

Trails and scenic highways provide opportunities 

for hiking, horseback riding, running, biking, 

and leisure driving. They also provide a means 

of connecting people to places, including parks 

and open spaces where they can partake in other 

recreational activities. The study area contains a 

wide range of trail types, including roads that have 

designated bikeways, paved trails separate from 

roadways, unpaved trails, and nationally recognized 

scenic, historic, and recreational trails. 

The Angeles Crest Scenic Highway is an important 

recreational feature of the study area. It is the only 

road that traverses through the entire Angeles 

National Forest from north to south; therefore it 

provides one of the best opportunities for people 

to access the forest via automobile. Many trailheads 

and recreational facilities are located along this 

highway. This road was designed expressly for 

recreational pleasure and features outstanding 

views and mountain scenery.

TRAILS

Trail corridors allow people to connect from 

their neighborhoods to open space and park 

resources, while experiencing their surroundings 

and contributing to their mental and physical 

well-being. Trail use also provides opportunities 

for social interaction. With the integration of 

educational and interpretive elements, trails also 

become spaces for connecting people to special 

places and their stories. The increasing demand 

for trails is exemplifi ed in the Public Opinions and 

Attitudes on Outdoor Recreation (1997) conducted 

for California State Parks which revealed through 

surveys that the top outdoor activity in the state 

is recreational walking. When asked if they would 

increase their participation in any particular 

activities if good opportunities became available, 

respondents indicated that recreational walking and 

trail hiking were in the top three activities in which 

they would engage.

Trail corridors often follow waterways, but they 

also have the ability to traverse and connect subwatershed areas as well as other open space areas. 

Trail corridors, depending on their widths, provide 

opportunities for integrating native vegetation 

and limited habitat and groundwater recharge 

and water quality improvement features such as 

bioswales.

Trails are maintained by a broad range of agencies. 

The Angeles National Forest offers 557 miles of 

hiking and equestrian trails which include 73 miles 

of National Recreation Trails and 176 miles of the 

Pacifi c Crest National Scenic Trail. Trails in the ANF 

are open to hiking and equestrian and mountain 

bikes use, except on the Pacifi c Crest National 

Scenic Trail and trails in designated wilderness areas.

In the urban areas, trails are primarily used for 

two purposes, recreation and non-motorized 

transportation. The County of Los Angeles manages 

the primary regional trail network. Their trails are 
Chapter 2: Resource Description Recreational Resources 89

described as multi-use “riding and hiking trails,” 

but not all of the trails are necessarily feasible for 

equestrian use. 

Trail data for this area is sparse and inconsistent 

because of the many agencies that manage trails. 

Agencies which have trail data include the Angeles 

National Forest, the Lower Los Angeles and San 

Gabriel Rivers and Mountains Conservancy, and 

the Los Angeles County Department of Parks and 

Recreation. Various municipal governments also 

collect trail data. Trails of the western Puente Hills 

have also been digitized by the Puente Hills Native 

Habitat Preservation Authority. 

National Trails 

The study area contains trails designated under 

the National Trails System, a network of scenic, 

historic, and recreation trails created by the National 

Trails System Act of 1968. These trails provide for 

outdoor recreation needs, promote the enjoyment, 

appreciation, and preservation of open-air, outdoor 

areas and historic resources, and encourage public 

access and citizen involvement. There are two 

categories of these trails in the study area, National 

Scenic and Historic Trails and National Recreation 

Trails (See map: Trails, Bikeways and Scenic 

Highways). 

National Scenic and Historic Trails preserve stories 

that are essential to a true understanding of the 

American experience. While National Scenic Trails 

and National Historic Trails may only be designated 

by an act of Congress, National Recreation Trails 

may be designated by the Secretary of Interior or 

the Secretary of Agriculture to recognize exemplary 

trails of local and regional signifi cance in response 

to an application from the trail’s managing agency 

or organization. National Scenic and Historic trails 

within the study area include the Pacifi c Crest 

National Scenic Trail, the Juan Bautista de Anza 

National Historic Trail, and the Old Spanish National 

Historic Trail. National Recreational Trails include 

the Gabrieleno Trail, the High Desert Trail, the Silver 

Moccasin Trail, and the West Fork Trail.

Established in 1968, The Pacifi c Crest National 

Scenic Trail spans 2,650 miles from Mexico to 

Canada through three western states, revealing the 

beauty of the desert, the Sierra Nevada, Transverse, 

and the Cascade Range Provinces. In the study 

area, the trail traverses the Angeles National Forest, 

entering at Cajon Pass and traversing across Blue 

Ridge, past Mt. Baden-Powell and eventually 

descending to Highway 14 at Agua Dulce where it 

enters the Sierra Pelona Mountains. The vistas from 

the trail in the Angeles National Forest include the 

Los Angeles Basin and Mojave Desert. 

The Juan Bautista de Anza National Historic Trail, 

which is managed by the National Park Service, 

commemorates the route followed by a Spanish 

commander, Juan Bautista de Anza, in 1775-76 

when he led a contingent of 30 soldiers and their 

families through what is now Mexico, Arizona, and 

California to found a presidio and mission near the 

San Francisco Bay. This unit of the National Park 

System has an auto route and a recreational route. 

The recreational route is currently planned through 

the Puente Hills to the Whittier Narrows area, and 

will coincide with the Schabarum/Skyline Trail and a 

portion of the Rio Hondo River Bike Trail.

The recently designated Old Spanish National 

Historic Trail commemorates the Santa Fe-to-Los 

Angeles route that sent dry goods west, and horses 

and mules east. The Old Spanish Trail forged the 

fi rst overland link to California for the east coast 

markets served by the Santa Fe Trail and the tradehungry markets of Mexico and New Mexico using 

El Camino Real de Tierra Adentro. The trail, which 

is more than 2,700 miles long and crosses New 

Mexico, Colorado, Arizona, Utah, Nevada, and 

California, goes through the Los Angeles region 

paralleling the Juan Bautista de Anza National 

Historic Trail.

The BLM and NPS will work with partners to provide 

recreation, public education, and interpretation, 

including: marking trails for public use, conducting 

historic and archeological research, developing 

visitor services and facilities, and protecting trailrelated sites and segments along the historic routes.

The Gabrieleno Trail follows the route of an original 

1920s road that ran from Pasadena north up 

the canyon past wilderness resorts and old rustic 

cabins. The road lost its appeal after the Angeles 

Crest Highway was built, but today has reinvented 

itself as a multiuse trail for hikers, horseback 

riders, mountain bikers, and birders. Much of the 

hike follows a gurgling stream past thick groves 

of live oak, sycamore, Douglas fi r, and big-leaf 

maple trees. Except for the fi rst half mile, the path 

is almost entirely in the shade, making it a great 

year-round hike. Some hikers prefer to begin at the 

northern end of the Gabrielino Trail, heading south 

into the forest from Switzer Falls Picnic Area and 

ending at the Arroyo Seco trailhead.

The High Desert Trail is a 27-mile backcountry 

trail that incorporates several trails, including the 

Burkhart Trail, Devil’s Punchbowl Trail, Manzanita 

Trail, and South fork Trail. The High Desert Trail 

system joins the San Gabriel Mountains with the 

Mojave Desert, and combined with the Pacifi c Crest 

Trail, it forms two small loops or one large loop. The 
90 Draft San Gabriel Watershed and Mountains Special Resource Study & Environmental Assessment 

trail affords the Pacifi c Crest Trail traveler a “high 

desert experience” alternative. 

The Silver Moccasin Trail is the oldest designated 

national recreation trail and stretches 51 miles 

through the Angeles National Forest Backcountry. 

The trial runs from Red Box down the West Fork 

of the San Gabriel River, up Shortcut Canyon and 

across the head of Big Tujunga to Charlton Flat 

and onto Chilao. From this point it follows along 

the Pacifi c Crest Highway to Mt. Baden-Powell and 

ends at Vincent Gap. This trail has been used by 

the Boy Scouts of America since 1942. Those that 

successfully complete the 5-day trip receive a Silver 

Moccasin badge.

The West Fork Trail is a paved trail which extends six 

miles along the West Fork of the San Gabriel River. 

This trail is popular for bicyclists in the region and 

provides access to excellent fi shing locations. 

Angeles National Forest Trails

In addition to the popular National Recreation 

Trails described above, the Angeles National 

Forest provides hundreds of miles of trails and fi re 

roads. John W. Robinson’s 100 Hikes in the San 

Gabriel provides good descriptions of these trails. 

They range from strenuous to easy and provide 

access to historic structures, high mountain peaks, 

and wilderness areas. With the exception of the 

wilderness areas, trails are generally open to 

mountain bikes. Equestrians also make use of the 

Angeles National Forest Trails. Many miles of trails 

are also available for off-highway vehicle use (OHV). 

County and Regional Trails

Regional trails and greenways are located 

throughout the study area linking various parks and 

open spaces. Schabarum (also known as Skyline) 

Trail extends 17 miles through the Puente Hills from 

Workman Mill Road in the west to Fullerton Road 

in the East. It serves as the spine for the preserve’s 

trail system and is maintained by Los Angeles 

County Parks. Schabarum Trail will also serve as a 

recreational route for the Juan Bautista de Anza 

National Historical Trail. 

Los Angeles County manages a regional trail 

network within the study area that connects 

regional and county parks. The County’s trail 

network connects all of the regional parks in the 

study area. A similar county trail network is planned 

for the Soledad Basin area and the Antelope Valley 

to the west and north of the Angeles National 

Forest.

The Marge Feinberg Rim of the Valley Trail Corridor 

encompasses the entire upper Los Angeles River 

Photos (top to bottom): 1. Schabarum Regional Park, 

Puente Hills. NPS photo. 2. Equestrians in Arroyo 

Seco. NPS photo. 
Chapter 2: Resource Description Recreational Resources 91

watershed area within the Angeles National 

Forest and portions of the Upper Santa Clarita 

River watershed. The trail is 150 miles long and 

approximately 60% complete. Trails connecting 

into the Rim of the Valley trail are the Backbone 

Trail, Pacifi c Crest Trail, De Anza Trail, and the Los 

Angeles River Parkway. Responsible jurisdictions are 

Los Angeles County, Ventura County, City of Los 

Angeles, US Forest Service, National Park Service, 

and California Department of Parks and Recreation 

(California Department of Recreation and Parks 

2002).

Bikeways

There are several types of bicycle paths and trails 

available in the study area. Class I bikeways feature 

off-street, bi-directional paved paths designated 

for cyclists. The San Gabriel River and Rio Hondo 

River trails are examples of Class 1 bike paths. 

These river bike trails also serve as regional trails 

and greenways, connecting communities and 

park areas. Los Angeles County’s San Gabriel River 

bike trail extends from the southern border of the 

Angeles National Forest in Azusa, all of the way to 

the Pacifi c Ocean. The total trail length is 39 miles. 

This trail includes access points from most major 

streets and direct access to 15 parks. The Rio Hondo 

River Trail links to the San Gabriel River Trail via the 

Whittier Narrows Recreation Area and converges 

with the Los Angeles River Trail near Downey, 

just south of John Anson Ford Park. The Whittier 

Greenway Trail is a 5-mile bicycle/pedestrian trail 

which replaced an abandoned right-of-way of the 

old Pacifi c Electric Railway.

Other bikeways are located along streets and roads. 

These include Class II bikeways, on-street, one-way 

striped lanes designated for cyclists, and Class 

III bike routes, on-street preferred bicycle routes 

designated by signs only.

The Los Angeles County Metropolitan 

Transportation Authority (Metro) developed a 

strategic plan in 2005 to describe a vision for 

bicycling as a viable transportation mode in Los 

Angeles County. The strategic plan establishes 

regional bicycle planning policies and provides tools 

for local agencies in creating local bicycle plans 

(Metro 2006). 

Equestrian Trails and Access

Equestrian users need strategic access points 

and staging areas to use the many trails available 

for equestrian use. Staging areas are located 

throughout the study area in Azusa, Duarte, Santa 

Fe Dam Recreation Area, San Dimas, Walnut, and 

the nearby Whittier Narrows Dam Recreation Area. 

Equestrian trails parallel the San Gabriel and Rio 

Hondo River Trails along many portions of these 

rivers. Some specifi c equestrian facilities include 

the Pico Rivera Bicentennial Park & Equestrian 

Center located at the northern end of the Whittier 

Narrows area. This facility holds 168 horse stalls 

and provides access to miles of trails. Included in 

the City of Industry is the Industry Hills Equestrian 

Center, a 400-staff equestrian center that provides 

access to 15 miles of trails for riding and hiking. The 

City of Walnut also maintains 26 miles of multi-use 

trails which are equestrian-oriented. 

Off-Highway Vehicle Trails

Trails for off-highway vehicle (OHV) use are found 

throughout the Angeles Forest in Soledad Basin and 

the Antelope Valley. Approximately 291 miles of 

unpaved road are open to OHV use on the Angeles 

National Forest while another 194 miles of unpaved 

road are closed to such use. It is estimated that the 

forest has 131,965 riders annually (Chavez and 

Knapp 2004). As OHV use grows in popularity, 

management conerns have arisen, including use of 

undesignated trails, soil erosion, water degradation, 

habitat destruction, the spread of endangered 

species, damage to cultural sites, and confl icts 

between different recreational user groups. 

Trail Connectivity

Another key issue is trail connectivity, or the 

degree to which trails connect to each other and 

to open space and park resources. Within the San 

Gabriel River watershed, the Los Angeles County’s 

regional trail system connects local parks, regional 

parks, and national forests. In the western portion 

of the study area, the Rim of the Valley Regional 

Trail connects open spaces along the western 

San Gabriel Mountains Foothills, the Verdugo 

Mountains, the San Gabriel and San Fernando 

Valleys, and the Santa Monica Mountains. This trail 

provides several connections to Angeles National 

OHV use. Angeles National Forest. NPS Photo. 
92 Draft San Gabriel Watershed and Mountains Special Resource Study & Environmental Assessment 

Forest Trails. Connectivity between cities and parks 

exists in some areas but there are many local trails 

that do not extend beyond jurisdictional borders. 

The Metropolitan Transit Authority has identifi ed 

connections for bike trails and commuter bike 

lanes on city streets. Los Angeles County Parks and 

Recreation has planned a connected trail system for 

the Antelope Valley area that will connect national 

forest lands to local communities. Planning is 

underway for this effort.

SCENIC ROADS AND HIGHWAYS

Angeles Crest Highway

The Angeles Crest Highway is the only major 

roadway that traverses the San Gabriel Mountains. 

The highway traverses from La Canada Flintridge 

through the heart of the mountains to Wrightwood, 

on the northeastern base. Completed in 1956, 

the highway was fi rst proposed in the early 1900s 

to provide access to the spectacular scenery, 

recreational areas, historic sites, geological features, 

and to mountain communities. In 1971 it was 

designated a California State Scenic Highway and 

in 1990, a National Forest Scenic Byway. From the 

highway, visitors can access campgrounds, ski areas, 

wilderness areas, historic sites, natural areas, picnic 

areas, and national recreation trails. 

OTHER AREAS THAT OFFER RECREATIONAL 

OPPORTUNITIES

Various land uses in the study area not expressly 

managed for public recreational opportunities also 

provide opportunities for recreation. These areas 

include schools, colleges and universities, botanical 

gardens, and cemetaries. 

Schools

Schools provide the opportunity to supplement 

open space resources in communities, particularly 

in areas that lack traditional parks and wildland 

areas. School grounds such as playing fi elds 

and playgrounds can be managed for multiple 

uses, providing community spaces close to 

neighborhoods when school is not in session, such 

as during afternoons, weekends, and holidays. 

Because the distribution of schools tends to be 

denser than the distribution of parks in the study 

area, they provide an important opportunity to 

provide close-to-home recreation opportunities. 

There are nearly 500 elementary, junior high, and 

senior high schools in the study area.

Colleges and Universities

Institutions of higher education provide multiple 

opportunities for providing recreation and 

conservation areas. In addition to having larger 

campuses than elementary, middle, and high 

schools, student populations are often energetic 

to engage in environmental issues. There are nine 

colleges and universities in the study area. Several 

colleges and universities managed open space for 

habitat conservation and recreation. For example, 

the Rio Hondo Wildlife Sanctuary at Rio Hondo 

College is available for research and educational use. 

Botanical Gardens

Botanical gardens, although not expressly managed 

for public recreation, provide an opportunity 

to walk and hike while learning about plant 

communities. Approximately 25 acres of the 

86-acre Rancho Santa Ana Botanical Gardens, 

managed by California Polytechnic University, 

Pomona, are within the study area. The garden is 

expressly designed to preserve and showcase native 

California plant communities. 

Cemeteries

While not traditionally considered open space, 

larger cemeteries and memorial parks are typically 

open, landscaped areas. Through public-private 

partnerships, there could be opportunities to 

develop watershed management practices in these 

areas. There are even examples of cemeteries being 

used by communities for recreational uses such as 

walking. Within the watershed, there are seven 

large cemeteries over 10 acres. Rose Hills Memorial 

Park in the Puente Hills is the largest cemetery in 

the study area. At 1,500 acres, it is also one of the 

largest in the world. 

The Angeles Crest Highway. 2005. NPS photo. 
Chapter 2: Resource Description Recreational Resources 93

Recreation Needs and Opportunities 

INTRODUCTION

The Los Angeles metropolitan region has struggled 

to provide adequate recreation opportunities for 

its growing urban areas since its fi rst population 

boom at the end of the 19th century. Throughout 

the 20th century, population growth and 

development in the region has far outpaced the 

creation of recreational facilities. This has occurred 

despite the completion of previous comprehensive 

recreation studies that called for investment in more 

recreational facilities.

Defi ciencies in recreation and open space remain 

for much of the Los Angeles Region. Over 15 

million people live in the larger metropolitan 

region and the California Department of 

Finance projects another 13 million 

residents by 2050 (California 

Department of Finance 2007a). 

With existing recreation and 

park areas in most cases 

already taxed beyond 

capacity, it is safe to 

assume that signifi cant 

efforts will need to 

take place to ensure 

suffi cient opportunities 

for diverse recreational 

experiences in the future. 

In addition, communities 

of color and children have 

disproportionately low access 

to parks and open space in Los 

Angeles County. See also Chapter 

7, Environmental Consequences, for a 

more discussion on current recreation trends. 

NEEDS 

Recreation Demand in Urban Areas

In addressing present and future open space 

concerns for the study area, disparities must be 

addressed regarding the disproportional access to 

park and recreational space. As recent reports from 

The Trust for Public Land (TPL) and the City Project 

indicate, public access, predominantly of minority 

populations, to parks and recreation facilities is a 

serious concern. According to TPL, Los Angeles 

County ranks at the bottom in comparison to the 

nation’s seven major cities (Boston, New York, San 

Francisco, Seattle, San Diego, and Dallas) in terms 

of providing access to parks for children. In fact, 

the report, based on 2000 census data, indicates 

that “more than 1.5 million children in Los Angeles 

County do not live within walking distance of 

a public park.” In most cases, parks in the Los 

Angeles region are not located near those areas 

with high concentrations of young children (Trust 

for Public Land 2004). 

The issue of accessibility is of particular concern 

when measuring existing open and park 

space in comparison to population densities. 

As demonstrated in the City Project’s work in 

Los Angeles, many families in the low income 

neighborhoods of the region often do not have 

cars nor are near public transportation systems that 

allow for access to regional parks. This is particularly 

true in the case of the 651,874-acre Angeles 

National Forest which, in making a simple per 

capita measurement (open space divided 

by population size), appears to 

indicate a sizeable measurement 

of potential recreation space in 

comparison to a local urban 

population. However, 

the aforementioned 

barriers to access and the 

inaccessibility of much 

of the forest’s terrain, 

skews this measurement 

signifi cantly. 

Public interest in open 

space and recreation in 

the region is signifi cant 

and concerted efforts are 

underway by a myriad of 

non-profi t organizations, local 

and municipalities, community 

groups, and private and public groups to 

procure and maintain open space in various areas 

throughout the Los Angeles region. Furthermore, 

the $2.6 billion Proposition 40 has further sparked 

this interest in public space allowing for funds to 

be allocated for environmental and park projects 

throughout the state of California (Trust for Public 

Land 2004).

Regional stakeholders such as the state land 

conservancies, land trusts, and other non-profi ts 

have worked diligently in their respective efforts 

to maintain and acquire park and open space in 

the region. The Rivers and Mountains Conservancy 

(RMC), one of eight conservancies in the California 

Resources Agency, is working to “preserve open 

space and habitat in order to provide for lowimpact recreation and educational uses, wildlife 

habitat restoration and protection and watershed 

Photo caption: The Santa Clara River. 2007. NPS photo. 
94 Draft San Gabriel Watershed and Mountains Special Resource Study & Environmental Assessment 

improvements within our jurisdiction.” Their 

work has been instrumental in the allocation of 

several new parks and open spaces including the 

Woodland Duck Farms (in coordination with the 

Trust for Public Land and the El Monte/Gibson Road 

Community Park. RMC has also been instrumental 

in their work on the San Gabriel River Corridor 

Master Plan

The Emerald Necklace Plan, headed by Amigos 

de los Rios, is working with local communities to 

develop a 17-mile loop of parks and greenways 

that connect to the San Gabriel River, creating 

additional open space for the local communities, 

and providing opportunities to improve water 

quality and create habitat. It is their vision to serve 

500,000 local residents with more than 1,500 acres 

of interconnected parks and open spaces. Amigos 

de los Rios’ work with local communities has 

resulted in the establishment of several parks along 

this necklace including Lashbrook Park, and the 

current rehabilitation of Rio Vista Park, both in the 

city of El Monte. 

National Forest Challenges and Demands

With over 10 million people within a 90-minute 

drive, the Angeles National Forest is highly used 

by local residents. Increasing recreation demands 

put increasing pressure on forest management. It is 

estimated that the recreational demand will increase 

by as much as 15-35% over the next two decades 

(UCLA Landscape Architecture Program 2006).

The effects of heavy recreational use in sensitive 

river corridors, particularly in the upper San Gabriel 

River Watershed, have impacted sensitive resources. 

With a mild climate, these areas receive year-round 

visitation. Additionally, on summer weekends, more 

than 10,000 visitors come to this area. Challenges 

include trash, graffi ti, tree-carving, and other illegal 

activities (UCLA Landscape Architecture Program 

2006).

As U.S. Forest Service budgets have been primarily 

allocated for wildfi re preparedness, the Angeles 

National Forest has struggled to provide adequate 

staffi ng and facility maintenance for such heavily 

used areas. Base budgets for non-fi re operations 

have remained relatively fl at since 1995. When 

adjusted for infl ation, such budgets have actually 

fallen. Meanwhile, recreation demands have 

continued to increase. With additional staffi ng, 

the U.S. Forest Service could expand education 

programs, ranger patrols, and facility maintenance 

to better address these needs (Richardson 2009).

Photos (top to bottom): 1. San Gabriel River bike 

trail, near Lashbrook Park. 2004. NPS photo. 2. The 

San Gabriel River. 2004. NPS photo. 3. Picnicking by 

Jackson Lake. 2007. NPS photo. 
Chapter 2: Resource Description Recreational Resources 95

Station Fire Effects on Recreation

A number of campgrounds and picnic sites within 

the ANF were damaged by the 2009 Station Fire. 

Those campgrounds damaged by the Station Fire 

include Monte Cristo, Mt. Pacifi co, Messenger 

Flats, Chilao, Valley Forge, West Fork, Devore, 

Millard, and Gould Mesa. Forest Service picnic 

areas damaged by the fi re are: Wildwood, Vogel 

Flat, Stoneyvale, Pines, and Switzer. The U.S. Forest 

Service anticipates that most campgrounds will be 

opened to the public when the burn closure ends, 

even though some features are fi re-damaged. 

Damaged tables, restrooms, etc. will be repaired or 

replaced following availability of funds. 

After the Station Fire, many forest roads were left 

without guard rails and regulatory and safety road 

signage, making them unsafe for regular traffi c. The 

damage to the surrounding land and hillsides also 

made the roads vulnerable to debris fl ow hazards 

during rain storm conditions. Because of this public 

safety danger, roads within the burned area are 

only open to residents, agency personnel, and 

construction crews. Trails were also damaged by 

fi res and subsequent erosion. Reconstruction of trail 

sections will also be necessary in many areas of the 

forest affected by the burn (USFS 2010).

OPPORTUNITIES

An inventory of open space with the urbanized 

portion of the study area (excluding the Angeles 

National Forest) demonstrates that opportunity 

areas often exist within the watershed corridors of 

the San Gabriel and Rio Hondo Rivers, in addition 

to tributary creeks including Walnut Creek and San 

Jose Creek. Flood zones both within and outside of 

these particular corridors provide open space with 

potential for recreational use. 

Additional opportunities for recreation and park 

development may also exist in industrial areas and 

Brownfi eld sites. Though remediation will no doubt 

be a concern, exhaustible extraction activities, 

namely oil and mineral sites, provide an opportunity 

for park and recreation space as these activities will 

at some point end. 

The eventual expiration of quarry activities, in such 

areas as Irwindale, Pico Rivera, and Baldwin Park, 

may open up signifi cant areas of open space within 

the San Gabriel River corridor, presenting additional 

opportunities for open space and recreation.

Utility right-of-way areas in many areas throughout 

the study area provide signifi cant tracts of opens 

space that are, in places, used for such activities 

as biking, walking, equestrian, use and plant 

nursery activities. Safety is no doubt a concern 

and negotiations with utility companies and city 

municipalities will need to take place to determine 

the appropriateness of space associated with any 

rights-of-way. 

Opportunities for further trail enhancements and 

connections exist throughout the study area. Efforts 

are underway to extend trail networks, particularly 

in and around the proposed Emerald Necklace 

project area. Additional efforts are underway to 

improve and link trail networks in Puente Hills, 

Schabarum Park, and the San Gabriel Foothills. 

Broader regional planning could greatly assist local 

agencies in realizing greater trail connectivity. 

As many of these opportunity areas span political 

boundaries and are beyond local municipality 

control, a regional, effective, and comprehensive 

approach should be taken when examining these 

opportunity sites. In doing so, barriers related to 

the relatively fragmented political character of these 

cities must be overcome so as to ensure effective 

and comprehensive management policies for 

regional recreation and open space planning.

Wildfl owers, Puente Hills. 2010. NPS photo. 
96 Draft San Gabriel Watershed and Mountains Special Resource Study & Environmental Assessment