Intermontane Plateaus and Basins

West of the Rocky Mountains lies an area of intermontane plateaus and basins. The intermontane means "between mountains". The region lies between the Rocky

Mountains and mountain ranges along the Pacific coast.

The intermontane area is long and broad, stretching from Washington to the border with Mexico. Most of the area lies in a "rain shadow" of the Pacific mountains. The mountains

block rain, and as a result, the lowland basins are dry.

Vegetation is sparse — scrub glasses and desert plants.

Except for the Colorado and Columbia rivers and their tributaries, the region has interior drainage. This means that water from the highlands flows into lakes or rivers in the area rather than to the ocean. However, the Columbia River flows west into the Pacific

Ocean and the Colorado River flows south into the Gulf of California. Some of the most impressive landscapes in the country are found in the region.

The best known is the Grand Canyon, one of the most beautiful landscapes in the world.

Fore some hundreds of million of years, the Colorado River slowly cut its way downward to the sea. The combined action of the river cutting downward and the gradual rise of the adjacent plateaus created some of the most breathtaking sights in America with rocks shaped by rain and wind into perfect arches, pillars and straggering walls which turn red at sunset.

Early settlers along the Colorado tried to alter the river's impact on the land by diverting for waters for irrigation. But each year the Colorado, fed by melting snows in the spring and early summer, and property low-lying lands along its route, destroying lives, crops, livestock property n a:e summer and early fall, the river often dried to a trickle, too low to

d .e-~ ла:ег crops and livestock withered and died. Eventually, a solution was

found - re construction of a large dam on the Colorado River was begun and it

was c o r : e:e: n "^35 Or ginally called Boulder Dam it was later renamed Hoover Dam

in honour of US F-es cent Herbert Hoover. It is 221 metres high, generating low-cost

hydroelectric power for use n Nevada, Arizona and California. Lake Mead backs up

arc л 176 kilometers behind the Hoover Dam creating America's largest man-made

-eservoir. Its waters irrigate more than a million acres of land in the US, and nearly half a

~ ion acres in Mexico.

The Mojave Desert and the Great Basin of Oregon, Utah, and Nevada lie within the

e: or The Great Salt Lake lies within the Great Basin. Death Valley, in California, is the

: est spot in the United States at 86 meters below sea level.

The Pacific Coastal Ranges

"he most western of the physical regions of the conterminous United States is made of the Pacific coast mountain ranges. Like the Rockies, they extend from Canada in the north to the border with Mexico in the south. The area is about 322 kilometers wide

- : m east to west. It has some of the highest mountains as well as some of the richest

mrmiand in the United States.

The interior range includes the Cascade Mountains in Washington and Oregon and

:~e Sierra Nevada in California. Within the Sierra Nevada is Mount Whitney at 4,418

- e:ers. Mount Rainier at 4,392 meters above sea level, is in the Cascade Range. Also in

ne Cascades are active volcanic peaks. Mount Helens erupted several times in recent

ears. Closer to the Pacific coast is a second range of mountains stretching from

Washington to California. In general, there are few good natural harbours along the west

: :ast. However, the most important are Puget Sound in Washington, and San Francisco

and San Diego bays in California.

Between the Pacific mountain ranges are hills, lower mountains, and valleys. In cenrai

California the Central or San Joaquin Valley extends between two ranges for almost

~24 kilometers. There are other valleys nearby. All of these valleys have rich soil and are

- ost important farm areas, producing fruits and crops exported world wide.

Alaska

In general, the landscape of Alaska is an extension of those in Canada and the con-

:e "ruinous 48 states to the south. The Pacific coastal mountains extend into the southeastern

part of Alaska called the Panhandle. Parts of the range dip beneath the ocean,

: eating many islands and inlets. These inlets make good harbours because of the deep

»va:er. The surrounding land is so steep, however, that it is difficult for land transportation

:Q ^each the harbours.

^"he coastal mountains stretch into Alaska from the Panhandle to create the

- aska Range in the south-central part of the state. Mount McKinley, the highest peak

- re United States, reaches an altitude of 6,194 meters in the range. Stretching to

• - e southwest of the Alaska Range are the Aleutian islands. They reach out 1,600 kilo-

- e:ers from the Alaska Peninsula. North of the Alaska Range is the broad lowland of

-e vukon River. The Yukon begins in Canada, travelling some 3,185 kilometers to

e-nptv into the Bering Sea. The valley's natural vegetation is needleieaf coniferous

'•rest.

Nor1n of the Yukon Valley is another mountain range, the Brooks Range. It too is an

arm of a mountain chain — the Rocky Mountains. South of the Brooks Range are areas

called r jskeg — land that is swampy and infested with insects in the summer and frozen

hare n v. -iter. Most of the land of northern and western Alaska has tundra vegetation.

The •••eas of Alaska is connected with the sea and the mines. Fisheries are the chief

source of wealth. Salmon is the biggest catch, taken in the rivers which flow down to the

3a: * c. mportant minerals are extracted in the mines: copper, uranium, nickel, tungsten

and many others. Oil has become another major source of income. In 1968, large

deposits of oil were discovered near Prudhoe Bay. The untouched beauty of nature

ar.racts many tourists too. Alaska was purchased from Russia in 1867 and officially

cecame the 49th state of the American Union in 1959.

Hawaii

Hawaii consists of hundreds of mostly volcanic islands stretching over 2897 kilometers

in the North Pacific Ocean. The larger inhabited islands are clustered in the southeastern

corner of the island chain. The largest island, Hawaii, is only 10,454 square kilometers

in area. The islands of Hawaii consist of the tops of volcanic mountains that rise

from the Pacific deep. The highest point in the islands is the active volcano of Mauna Kea

on the island of Hawaii. It reaches 4,205 meters above sea level. The southerly marine

position means a mild, warm sunny climate all the year round, with adequate rainfall from

steady northeast winds and snow on the peaks in winter. Much of the islands is forested

with a tropical forest, including such trees as the eucalyptus and native hardwoods like

the koa. Less than 8 per cent of the land is cultivated. Sugar and pineapples are the chief

cash crops. Hawaii's strategic position for trans-Pacific communications makes it an

important sea and air transport center.

Pearl Harbor, an important military base of the United States, is located here. It is

•veil known over the world because of the surprise attack by the Japanese on the navy

sh ps there on 7 December 1941 which brought the US into World War II. Nearly 80 per

cent of the civilian population live in the capital, Honolulu. Hawaii's most important

source of income is tourism. With the growing popularity of surfing lots of surfers come

:: Hawa i to enjoy the challenges of the highest surfs in the world in wintertime. In 1959,

- a = cecame the fiftieth state of the United States.