Unit 1 Overview: Exploring the Local Landscape
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California History-Social Science, Grade 3, Standard 1: Students
describe the physical and human geography and use maps, tables, graphs,
photographs, and charts to organize information about people, places and
environment in a spatial context by:
1. identifying geographical features found in their local region (e.g., deserts,
mountains, valleys, hills, coastal areas, oceans, lakes)
2. tracing the ways in which people have used the resources of the local
region and modified the physical environment (e.g., a dam constructed
upstream changed a river or coastline)
California Historical and Social Sciences Analysis Skills:
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Students use map and globe skills to determine absolute locations of places and
interpret information available through a map’s or globe’s legend, scale and symbolic
representations.
Students judge the significance of the relative location of a place …
Students pose relevant questions about events they encounter in …photographs, maps
Students identify the human and physical characteristics of the places they are
studying and explain how those features form the unique character of those places.
Description of this Unit
The unit begins with the construction of a “Flip-Book” titled “Where I Live.” In Lesson
2, students study geographical terms and definitions and use local maps to identify key
geographical features of the Coachella Valley. In Lessons 3 and 4, students construct a
map of the local region and identify key geographic landforms and human-made features
of the area. The focus in Lesson 5 is on how the physical environment of the local region
has been modified over time. Students interview long-term residents to ask about the
changes they have observed. Several writing projects, including a descriptive paragraph
of a physical feature and a compare/contrast paragraph describing how the region has
changed over time, reflect the Grade 3 writing strategies and writing application
standards. Extensions are also provided for English Language Learners (ELL). All
projects are compiled at the end of the unit into an Atlas of the Coachella Valley.
Focus Questions for Unit 1
Lesson 1: What are the geographical features of a place?
Lesson 2: Where is our community located?
Lesson 3: What physical features are unique to the local region?
Lesson 4: How do people change the places where they live? What are the human-made
features of the local region?
Lesson 5: How have people changed or modified the physical environment of the region?
Unit 1: Exploring the Local Landscape
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Coachella Valley Geography Overview
The Coachella Valley is an irrigated agricultural and recreational desert valley located in
the lower Colorado Desert region of southern California east of Los Angeles. The valley
extends for approximately 45 miles in Riverside County southeast from the San
Bernardino Mountains to the Salton Sea. The valley is approximately 15 miles wide
along most of its length. The Coachella Valley is bounded on the west by the San Jacinto
Mountains and the Santa Rosa Mountains and on the north and east by the Little San
Bernardino Mountains. The highest peaks in the surrounding mountains are Mt. San
Jacinto (10,804') and Mt. San Gorgonio (11,499'). Elevations on the valley floor range
from 1600' above sea level at the upper end of the Valley near Palm Springs to 250'
below sea level at the Salton Sink. For additional background information, refer to
the next section of this unit titled Geography of the Coachella Valley.
Recommended Map Resources for the Unit
It is suggested that the teacher collect a series of maps for students to use including a
world map, a United States map, a map of California, a variety of maps of the local
region, a map of the local community, and a map of the school and its neighborhood. A
globe, wall maps, and laminated desk maps are also useful. It is helpful if students have
access to a children’s atlas.
Recommended maps include:
 Desert Country – A Recreational Map of California Deserts. Compass
Maps (800) 441-6277 or www.compass-maps.com
 Los Angeles & Orange Counties and Vicinity; San Diego Region; and,
California maps from the American Automobile Association (AAA).
 California Desert District- Palm Springs. United States Department of the
Interior Bureau of Land Management, Denver, CO. BLM Special Edition
998 Surface Management Status Desert Access Guide. 1:1000,000 Scale
topographic map. ISBN 0-607-91386-X.
Map resources may be obtained at some of the following locations:
 Map stores such as Desert Map & Aerial in Palm Desert (760) 346-1101, the local
Chamber of Commerce, the Visitor’s Bureau, the American Automobile Association
(AAA), book stores, gas stations, and the front of the telephone directory. Often public
libraries distribute such maps. The Thomas Bros. maps for Riverside County are
useful for finding streets in the local community.
For additional map resources, refer to Resources for Geography of the Local Region
at the end of this curriculum guide.
Unit 1: Exploring the Local Landscape
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Geography of the Coachella Valley
The Coachella Valley is an irrigated agricultural and recreational desert valley located in
the lower Colorado desert region of southern California east of Los Angeles. The valley
extends for approximately 45 miles (72 km) in Riverside County southeast from the San
Bernardino Mountains to the Salton Sea. The valley is approximately 15 miles (24 km)
wide along most of its length.
The Coachella Valley is bounded on the west by the San Jacinto Mountains and the Santa
Rosa Mountains and on the north and east by the Little San Bernardino Mountains. The
highest peaks in the surrounding mountains are Mt. San Jacinto (10,804') and Mt. San
Gorgonio (11,499'). Elevations on the Valley floor range from 1600' above sea level at
the upper end of the Valley near Palm Springs to 250' below sea level at the Salton Sink.
The Salton Sea today covers over 380 square miles of surface water making it the largest
lake in California. Its width varies from 9 to 15 miles and is about 35 miles long. The sea
contains 115 miles of shoreline. Through evaporation (leaving the minerals and salts to
become concentrated), the Salton Sea is about one-third saltier than the ocean. The
surface level of the Salton Sea is about 232 feet below sea level. The Sea varies in depth
with the gentle valley slope to about 51 feet deep. Because of the abundant fish life in the
Sea, the waters have become home to numerous bird species.
The Coachella Valley is part of the Whitewash watershed that drains into the Salton Sea.
Approximately 7% of the flow into the sea is from the Coachella Valley. Because the
lake is shallow, has no outlet and receives salts and water from agricultural drainage,
salinity and nutrient levels are rising and the sea has been designated as an impaired body
of water by the State Regional Water Quality Control Board.
The San Andreas Fault crosses the valley from the Chocolate Mountains in the southeast
corner and along the centerline of the Little San Bernardino Mountains. The fault is
easily visible along its northern length as a strip of greenery against an otherwise bare
mountain. The Chocolate Mountains are home to a United States Navy live gunnery
range and are mostly off-limits to the public.
Climate Rainfall is extremely limited with average annual precipitation rates of 2 to 4".
Most rainfall occurs during winter months though high intensity rains can sometimes
occur during the mid-summer producing flash floods and severe erosion.
Annual temperature variations in the Coachella Valley are extreme with occasional
winter lows in the mid 20s (F) and occasional summer highs in the mid 120s (F). The
mean annual temperature is 74(F). The Valley offers a 300 day frost free growing season
with some crops grown successfully through the entire year. (Refer to Coachella Valley
Weather Information.)
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Seasonal winds can be a problem in some regions of the Valley. The valley's northwest
entrance from the Inland Empire along Interstate 10 is known as the "San Gorgonio Pass"
and is one of the windiest places on earth. Cool coastal air is forced through the pass and
mixes with the hot desert air, making the San Gorgonio Pass one of only three ideal
places in California for steady, wind-generated electricity. Hundreds of huge wind
turbines spread across the desert and hills on either side of the highway greet visitors as
they approach the crest of the pass and have become somewhat of a symbol of the area.
The state's other wind farms are in the Tehachapi Pass between Mojave and Bakersfield
and in the Altamont Pass near Livermore. Windstorms most frequently occur in the late
spring and can cause extensive damage to unprotected soils, plants, structures and
vehicles. Airborne dust carried by these winds can compromise air quality and respiratory
health.
The Coachella Valley was once dominated by nearly 100 square miles of sand dunes;
today there is fewer than 5% of that habitat remaining in viable condition. Over the years,
the lure of mild winter temperatures and beautiful scenery has resulted in an explosion of
human development. As canyons filled with houses, development pushed into the valley's
center, blocking the vital sand movement processes the keep the dunes alive. Today the
majority of the remaining, viable dune habitat is contained in the Coachella Valley
Preserve system. The focus of the preserve system is the protection of the desert sand
dunes, but to accomplish that, sand source areas and sand movement corridors also need
to be protected. The Coachella Valley Preserve system was also designed to protect an
endemic, threatened animal, the Coachella Valley fringe-toed lizard, Uma inornata. To
protect the entire dune ecosystem, several additional habitats were included. These
additional habitats are creosote bush scrub, mesquite hummocks, and eleven different
palm oases. It is the palm oases that lure the many visitors to the Coachella Valley
Preserve every year. These verdant, lush habitat islands, often with pools of water or
small streams, are in stark contrast to the otherwise sere brown desert. The fragile dunes
are protected from un-guided access, but the palm oases are all available to explore.
Coachella Valley soils originate from two main sources: sediment deposits from ancient
Lake Cauhilla and weathered rock from the surrounding mountains. Deposited by wind
and water, these parent materials combine to create a large variety and complex
distribution of distinctive soil types throughout the Valley. In general, soils at lower
elevations of the Valley floor are composed of fine textured sedimentary materials that
are classified as silts and silty loams. Much of Coachella Valley's production agriculture
is found on these fine textured soils. They have greater water holding capacities than the
coarser sands, gravels and rocks that are found at higher elevations near the surrounding
mountains and alluvial fans.
Water is brought into the region by artesian wells and by the Coachella Canal (123
mi/198 km long). The Coachella Canal, a concrete-lined aqueduct built between 1938
and 1948 as a branch of the All-American Canal, brings water from the Colorado River to
the valley. This canal system irrigates more than 630,000 acres (254,961 hectares) and
has greatly increased crop yield in the area; however, problems of drainage and salinity
exist. The All-American Canal is part of the federal irrigation system of the Hoover
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Dam. Built between 1934 and 1940 across the Colorado Desert, the canal is entirely
within the United States and replaces the Inter-California Canal, which passes through
Mexico. The Imperial Dam, northeast of Yuma, Arizonia, diverts water from the
Colorado River into the All-American Canal, which runs west to Calexico, California.
The Colorado River Aqueduct, which provides drinking water to Los Angeles and San
Diego, crosses the northeast end of the valley along the base of the Little San Bernardino
Mountains.
Although geographically the Coachella Valley is the northwestern extension of the
Colorado Desert to the southeast, the irrigation of over 100,000 acres (405 km²) of the
valley since the early 20th century has allowed widespread agriculture. In its 2003 annual
report, the Coachella Valley Water District listed the year's total crop value at over $550
million or just over $8000 per acre ($2/m²). Truck crops, dates (the majority of U.S.
production), citrus fruits, and alfalfa are grown in the region. The products are shipped
from the city of Coachella, which serves as a distribution point for the valley.
For additional information, refer to http://www.cvconservation.org/coachellavalley.html
For Coachella Valley demographics see http://www.census.gov/
The Imperial Valley is a fertile region in the Colorado Desert of southeastern California
that extends southward into northwestern Mexico. Once part of the Gulf of California,
most of the region is below sea level. Its lowest point is -232 ft (-71 m) at the southern
shore of the Salton Sea. The Imperial Valley receives only about 3 inches (7.6 cm) of rain
annually. The valley experiences extremely high temperatures (115°F/46°C) and has a
great daily temperature range. Having one of the longest growing seasons in the United
States (more than 300 days), the valley can, with irrigation, support two crops a year. It
was first irrigated in 1901. Several disastrous floods on the Colorado River in 1905–6
inundated the area. Not until 1936, with the completion of Hoover Dam, was the valley
safe from floods. Approximately 1 million acres (404,700 hectares) have been irrigated,
chiefly by the All-American Canal. The valley is an important source of winter fruits and
vegetables for the northern areas of the United States. Cotton, dates, grains, and dairy
products are also important. Brawley, Calexico, and El Centro are the main U.S. cities in
the valley. Mexicali, Mexico, also in the valley, is the center of Mexico's important
cotton-growing district.
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