valley fever: see coccidioidomycosis.

rift valley, elongated depression, trough, or graben in the earth's crust, bounded on both sides by normal faults and occurring on the continents or under the oceans. The central flat block forming the trough slips downward relative to the crustal blocks on either side. The appearance is that of a fallen keystone in a broken arch. Rift valleys form by tensional forces, typically those associated with the initiation of plate separation (see plate tectonics). The development of a rift valley in a continent is believed to be a precursor to the breakup of the continent and the development of a new ocean basin by seafloor spreading. Rift valleys, such as the Red Sea and the African rift valleys, are commonly the sites of volcanism and the locus of much earthquake activity.

lily of the valley, common name for either of the two species of Convallaria, spring-blooming perennials of the family Liliaceae (lily family). C. majalis, the species usually in cultivation, is native to Eurasia; C. montana, a slightly larger plant, grows in the Appalachian Mts. Lilies of the valley live in shady places and have delicate bell-shaped, fragrant white flowers growing on a stalk between two shiny leaves. The plant was long used medicinally for cardiac disorders and contains poisonous substances. It is a symbol of humility in religious painting. Lily of the valley is classified in the division Magnoliophyta, class Liliopsida, order Liliales, family Liliaceae.

Wyoming Valley, c.20 mi (30 km) long and 3 to 4 mi (4.8-6.4 km) wide, in Luzerne co., NE Pa., through which flows the Susquehanna River. Wilkes-Barre is the major city of this once-rich anthracite coal region. The valley was the scene of a long contest between Connecticut and Pennsylvania over conflicting land claims based on 17th-century charters. After the Susquehanna Company purchased (1754) land there at the Albany Congress, a temporary settlement of the region in 1762-63 led to the first permanent settlement in 1769 and the building soon after of Forty Fort. The First Pennamite War (1769-71) between the Connecticut and Pennsylvania settlers ensued, but rapid settlement of the area continued. In 1774, Connecticut set up the town of Westmoreland, from which representatives were sent to the Connecticut legislature. During the American Revolution, the valley settlers were attacked (1778) by Loyalist commander John Butler and a party of Tories and Iroquois allies; nearly 400 men, women, and children were killed. The massacre is described in Thomas Campbell's poem, Gertrude of Wyoming (1809). In 1782 a Continental Congress court of arbitration decided to grant the land in favor of Pennsylvania, but the Connecticut settlers refused to leave, and the Second Pennamite War (1784) ensued. Finally, through the Compromise Act of 1799, the Pennsylvania legislature secured a means of settlement with the Connecticut claimants.

Valley of Ten Thousand Smokes: see Katmai National Park and Preserve.

Valley Stream, village (1990 pop. 33,946), Nassau co., SE N.Y., on Long Island, a residential suburb of New York City; inc. 1925. Kennedy International Airport is to the west. Valley Stream is the site of Green Acres Mall, one of the largest shopping centers in the United State.

Valley Station, uninc. town (1990 pop. 22,840), Jefferson co., N central Ky, S of Louisville. It is a primarily residential community.

Valley Forge, on the Schuylkill River, SE Pa., NW of Philadelphia. There, during the American Revolution, the main camp of the Continental Army was established (Dec., 1777-June, 1778) under the command of Gen. George Washington. The winter was severe, food and clothing was inadequate, and illness and suffering pervaded the camp. The number of ragged and half-starved troops dwindled through desertion; the remaining men, about 11,000, talked of mutiny but were held together by their loyalty to Washington and to the patriotic cause. Two distinguished foreigners, French General Lafayette and Prussian General Steuben, shared the misery of the troops; Steuben drilled and organized the men, transforming the loose-jointed army into an integrated force. The site is included in Valley Forge National Historical Park (see National Parks and Monuments, table).

Turner Valley, village (1991 pop. 1,352), SW Alta., Canada, at the foot of the Rocky Mts., on the Sheep River, SW of Calgary. It is in the center of the Turner Valley oil and natural gas fields, opened in 1914. The village has sulfur and propane and pentane gas plants.

Tennessee Valley Authority (TVA), independent U.S. government corporate agency, created in 1933 by act of Congress; it is responsible for the integrated development of the Tennessee River basin. The history of TVA began in the early 1920s, when Senator George William Norris sponsored a plan to have the government take over and operate Wilson Dam and other installations that had been built by the government for national defense purposes during World War I at Muscle Shoals, Alabama. However, legislation to this effect was vetoed in 1928 and in 1931 by Presidents Calvin Coolidge and Herbert Hoover. The 1933 TVA Act, redrafted by President Franklin D. Roosevelt, went far beyond the earlier proposals and launched the federal government into a vast scheme of regional planning and development—an undertaking that became the model for similar river projects.

The establishment of the TVA marked the first time that an agency was directed to address the total resource development needs of a major region. TVA was instructed to take on the problems presented by devastating floods, badly eroded lands, a deficient economy, and a steady outmigration—all in one unified development effort. The act provided for the integrated development of the whole Tennessee River basin, an area of about 41,000 sq mi (106,200 sq km) that covers parts of seven states. The TVA is governed by a three-person board of directors. The fact that its main offices are located in the region, rather than in Washington, D.C., allows the TVA to maintain a close working relationship with the people of the region.

Facets and Activities of the TVA

In 1998 the TVA generated more electricity than any other U.S. utility, supplying 8 million residents. The most noteworthy feature of TVA is the system of multipurpose dams and reservoirs that have contributed greatly to the economic life of the area. There are some 50 dams in the hydroelectric system with an installed capacity in excess of 6 million kW. To meet the growing demand for power over and above the hydroelectric capacity of the system, the TVA began in 1940 to construct steam-generating facilities. By the late 1990s, 62% of the TVA's installed capacity was provided by coal-burning steam plants.

Steadily mounting power demands encouraged TVA to add nuclear power plants in the early 1970s. Design and management flaws and a 1975 accident at Browns Ferry resulted in plant closures and construction delays, but by 1996 three facilties (Watts Bar, Sequoyah, and Browns Ferry) were open and operating.

Electric power from all sources is allocated with a view to promoting the widest possible use of electricity throughout the area—with local municipalities, state and federal agencies, and farmer cooperatives receiving priority over private utility companies and industries. The availability of low-cost electricity has attracted large numbers of businesses and industries to the area, and a 630-mi (1,014-km) navigation channel extending from the mouth of the Tennessee River to Knoxville, Tenn., has been responsible for an enormous increase in river traffic, chiefly in coal, construction material, grain, petroleum, chemicals, and forest products.

Other TVA activities, carried out in cooperation with local authorities, include land conservation; environmental research; tree planting; malaria control; the development of fish, wildlife, and mineral resources; social and educational programs; and the establishment of recreational facilities along the banks of its reservoirs, including the Land Between the Lakes, in W Kentucky and W Tennessee.

Financing the TVA

Throughout much of the history of the TVA, opponents of the authority have argued that it is too costly and that government should not compete with private enterprise. In 1959, Congress authorized the TVA to issue bonds and notes to be used in financing needed additions to power system capacity. The power system became self-financing and by the early 1990s had paid back more than $2.5 billion into the U.S. Treasury. Congressional funding of the TVA's nonpower programs was phased out in the late 1990s, leaving it totally self-supporting.

The TVA Today

By the 1960s many of the regional problems of underdevelopment had been overcome, per capita income had increased dramatically, and rapid outmigration had ended. However, the TVA continues to seek ways to make the largely rural area an attractive alternative to overcrowded cities. In the late 1960s and early 70s the TVA began to place greater emphasis on environmental protection as industrialization and rising living standards resulted in greater demands on the environment. In the conflict between economic and environmental objectives the TVA sought a suitable balance, particularly in its power program. Despite the TVA's environmental protection efforts, the agency has been criticized principally by environmental groups. Controversial issues have involved construction of the Tellico Dam and Reservoir on the Little Tennessee River, the nuclear power program, and the TVA's purchase of pollution credits from Wisconsin Power and Light in 1992.

Ten Thousand Smokes, Valley of: see Katmai National Park and Preserve.

Sun Valley, mountain resort city (1990 pop. 938), alt. c.6,000 ft (1,830 m), Blaine co., S central Idaho; inc. 1967. It is a popular year-round resort with both winter and summer sports. It was founded as a ski resort in 1936 by W. Averell Harriman, then board chairman of the Union Pacific RR; the railroad purchased the land and built the resort to attract more passenger traffic to the West. In 1964 it was sold to a land-development corporation; in 1967, Bill Janss, a former Olympic skier, became sole owner. The Hemingway Memorial, on a bluff overlooking a swift-flowing trout stream, was dedicated in 1966.

Strawberry valley project, N central Utah, developed by the U.S. Bureau of Reclamation for irrigating lands S of Utah Lake; constructed 1906-13. The water of Strawberry River and its tributaries is carried by a tunnel through the Wasatch Range to a tributary of the Spanish Fork and is used for lands in the vicinity of Salem, Spanish Fork, Springville, Payson, and Santaquin. The project is supplemented by the Central Utah project.

Squaw Valley, valley, NE Calif., in the Sierra Nevada Mts., NW of Lake Tahoe. A well-known ski and winter recreational resort, it was the site of the 1960 Winter Olympics. Ski lifts and trails are on Squaw Peak (8,960 ft/2,731 m high).

Spring Valley. 1 Uninc. community (1990 pop. 55,331), within the confines of San Diego, San Diego co., SW Calif., on Sweetwater Lake. It is a rapidly growing residential community, with some light industrial production (transportation equipment and paper and metal products). The Bancroft Ranch House Museum (1856) is a national historic landmark. 2 Residential village (1990 pop. 21,802), Rockland co., SE N.Y., near the N.J. line; inc. 1902. It is a fast-growing suburb with office complexes and shopping malls.

Simi Valley, city (1990 pop. 100,217), Ventura co., SW Calif. in an oil, fruit, and farm region; laid out 1887, inc. 1969. Highly residential, the city also produces a variety of light manufactures, including electrical, electronic, computer, and medical equipment; clothing; metal and plastic products; and furniture. The population of Simi Valley more than doubled between 1970 and 2000, with the growth of the Los Angeles metropolitan area. Of interest are a historical park, Native American caves, and the old stagecoach road.

Silicon Valley, an industrial region, approximately 20 mi (32 km) long, in the Santa Clara Valley between Palo Alto and San Jose, mainly in Santa Clara and San Mateo counties, W central Calif., where many computer manufacturing and design companies are located. Computer-software and other high-technology industries are also there. The name derives from high-purity silicon used in making the semiconductors used in computers.

Shenandoah valley, part of the Great Valley of the Appalachians, c.150 mi (240 km) long, N Va., located between the Blue Ridge and the Allegheny mts. The valley is divided into two parts by Massanutten Mt., a ridge c.45 mi (70 km) long and c.3,000 ft (915 m) high. The Shenandoah River, c.150 mi (240 km) long, rises in two forks on either side of the ridge, uniting near Front Royal, Va., and flowing northeast to enter the Potomac at Harpers Ferry, W.Va. The Shenandoah valley was first explored in the early 1700s. The valley was an important corridor in the westward pioneer movement, and it became a rich agricultural area with farm-land, orchards, and pastures. During the Civil War, the valley was the ideal avenue of approach for the Southern invasion of the North, and it served as one of the Confederates' principal storehouses. Shenandoah figured in the "valley campaign" of Stonewall Jackson in 1862; Lee retreated through the valley after being checked in the Antietam campaign (1862) and the Gettysburg campaign (1863). By early 1865, the valley was completely lost to the South. The principal cities are Winchester, Front Royal, Staunton, and Waynesboro. The many recreational areas include Shenandoah National Park, in the surrounding uplands.

Salt River valley, irrigated region around the lower course of the Salt River, which rises in mountain streams near the Mogollon Rim of the Mogollon Plateau and flows southwest to join the Gila River in S central Arizona. Phoenix is the main city of the latter Ariz. region. Native Americans used the Salt River for irrigation many centuries ago. In the 19th cent., American settlers began irrigated farming in the valley, and the Mormons used some of the old Native American canals at Mesa, Ariz. The Salt River project, the first large irrigation scheme undertaken under the Federal Reclamation Act of 1902, is one of the most economically successful projects in North America. It began in 1903 when construction started on the Roosevelt Dam in a canyon E of Phoenix. The dam, forming Roosevelt Lake behind it, impounds enough water to irrigate fields for about two years even if no rain falls. Other dams were built between 1922 and 1946 to supply water and power. The region is a rich producer of citrus fruits, lettuce, melons, and other crops. A major factor in the Salt River project's success is the long season without frost; the climate also makes this area an attractive winter resort.

North Valley Stream, uninc. town (1990 pop. 14,574), Nassau co., SE N.Y., on Long Island. It is chiefly residential.

Napa Valley, Calif.: see under Napa.

Moreno Valley, city (1990 pop. 118,779), Riverside co., S Calif., inc. 1984. In 1990, Moreno Valley was California's fastest-growing city, with a population increase of more than 300% between 1980 and 1990, but major reductions in the military and aerospace industries brought an abrupt halt to growth in the mid-1990s. The city's economic situation has since improved. Industries include recreational vehicles, rolling steel doors, modular structures, home construction and improvement enterprises, and retailing. March Air Force Base (now March Air Reserve Base), which employed a large proportion of the city's workers and is the oldest base in the W United States, experienced a major manpower reduction in the 1990s. Part of the former base is now under development as an air cargo port. Moreno Valley is the seat of a branch of Chapman Univ. Nearby is a state park with recreational facilities.

Monument Valley, scenic arid region, c.2,000 sq mi (5,000 sq km), SE Utah and NE Ariz. Located in the Navajo Indian Reservation, Monument Valley is not a true valley but an area of monolithlike buttes and pinnacles that rise as much as 1,000 ft (300 m) above the desert. Best known as the backdrop for John Ford's Stagecoach (1939) and other westerns, the predominantly red and orange sandstone, siltstone, and shale landscape is sacred to the Navajos because of its burial grounds and holy places. Anasazi and older remains are also found in the valley. Monument Valley Navajo Tribal Park (29,817 acres/12,076 hectares) contains some of the most notable features, including El Capitán (7,100 ft/2,170 m), known to the Navajo as Algathla.

Mill Valley, city (1990 pop. 13,038), Marin co., W Calif., a suburb on Richardson Bay, an inlet of San Francisco Bay; inc. 1900. It is a residential community set in heavily timbered hills and valleys; redwood trees predominate. Golden Gate Baptist Theological Seminary and an artists' colony are there. Mt. Tamalpais State Park is adjacent to the city, and Muir Woods National Monument (see National Parks and Monuments, table) is nearby.

Long Valley, caldera, c.10 by 20 mi (15 by 30 km), Mono co., E Calif., at the eastern edge of the Sierra Nevada. Formed by a catastrophic eruption c.730,000 years ago, Long Valley and nearby areas have been the scene of volcanic activity for more than 3 million years. The resort city of Mammoth Lakes is in the caldera in the southwest section, in an area of many small lakes. Nearby Mammoth Mt., 11,050 ft (3,368 m), on the southwest rim of the caldera, is composed of about dozen lava domes and formed from 200,000 to 50,000 years ago. Devils Postpile National Monument, outside the caldera to the west of Mammoth Mt., protects basaltic columns, some 60 ft (18 m) in height, that formed from lava that erupted 200,000 to 100,000 years ago. North of Mammoth Lakes, the Inyo and Mono crater fields stretch along a 30-mi (50-km) system of volcanic fissures from the northwestern caldera floor toward Mono Lake (87 sq mi/225 sq km). Eruptions in this area began in the caldera 300,000 years ago, moving to the north over time; the most recent eruption formed Paoha Island in Mono Lake and ended c.A.D. 1850. Since the late 1970s seismic and other geologic activity in the Long Valley area has led to concern over the possibility of a new eruption.

Kobuk Valley National Park, 1,750,737 acres (709,048 hectares), NW Alaska. Located in rugged terrain N of the Arctic Circle, the park embraces the central valley of the Kobuk River, a centuries-old transportation route with many archaeological sites. The 70-mi (113-km) Salmon Wild River lies entirely within the park. Other features include caribou migration routes and the Great Kobuk Sand Dunes. Proclaimed a national monument in 1978, it was designated a national park in 1980. See National Parks and Monuments (table).

Indus valley civilization, ancient civilization that flourished from about 2500 B.C. to about 1500 B.C. in the valley of the Indus River and its tributaries, in the northwestern portion of the Indian subcontinent, i.e., present-day Pakistan. At its height, its geographical reach exceeded that of Egypt or Mesopotamia. Since 1921 this civilization has been revealed by spectacular finds at Mohenjo-Daro, an archaeological site in NW Sind, and at Harappa, in central Punjab near the Ravi River. These sites, each of which measures more than 3 mi (5 km) in circumference, were once great urban centers, the chief cities of the Indus civilization. They had large and complex hill citadels, housing palaces, granaries, and baths that were probably used for sacred ablutions; the great bath at Mohenjo-Daro was c.40 ft (12 m) long and 23 ft (7 m) wide. Beyond the citadels were well-planned towns, laid out in rectangular patterns. Houses, often two-storied and spacious, lined the town streets; they had drainage systems that led into brick-lined sewers. The economy of the Indus civilization was based on a highly organized agriculture, supplemented by an active commerce, probably connected to that of the ancient civilizations of Mesopotamia. The arts flourished there, and many objects of copper, bronze, and pottery, including a large collection of terra-cotta toys, have been uncovered. Most notable, however, are the steatite seals, exquisitely engraved with animal figures and often bearing a line of pictographic script. On some seals are depicted a bo tree or, as some authorities hold, a Babylonian tree of life, and others have as their central figure the god Shiva, who later became preeminent in the Hindu pantheon. The writing, long a riddle to archaeologists, has yet to be satisfactorily deciphered; the language appears to be structurally related to the Dravidian languages. The origin, rise, and decline of the Indus valley civilization remain a mystery, but it seems most probable that the civilization fell (c.1500 B.C.) to invading Aryans.

Imperial Valley, fertile region in the Colorado Desert, SE Calif., extending S into NW 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. Receiving only c.3 in. (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, Calif., 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.

Hunter Valley, region of New South Wales, SE Australia. The Hunter River and its tributaries occupy this valley S of the Mt. Royal Range. The land in the upper valley is used for livestock grazing, dairying and agriculture. The lower valley is an important center for coal mining and wineries.

Hetch Hetchy Valley, in Yosemite National Park, central Calif., on the Tuolumne River. It once rivaled Yosemite Valley in beauty and grandeur. O'Shaughnessy Dam (completed 1923; enl. 1938) turned the valley into a lake c.9 mi (14 km) long, which is used for generating power and for supplying water to San Francisco by an aqueduct 156 mi (251 km) long.

Great Rift Valley, geological fault system of SW Asia and E Africa. It extends c.3,000 mi (4,830 km) from N Syria to central Mozambique. The northernmost extension runs S through Syria and Lebanon, the Jordan valley, the Dead Sea, and the Gulf of Aqaba. It continues into the trough of the Red Sea and at the southern end branches into the Gulf of Aden, where it continues as part of the Mid-Oceanic Ridge of the Indian Ocean. The main section of the valley in Africa continues from the Red Sea SW across Ethiopia and S across Kenya, Tanzania, and Malawi to the lower Zambezi River valley in Mozambique. Many small lakes in Ethiopia and several long narrow lakes, notably lakes Turkana and Nyasa, lie on its course. Just N of Lake Nyasa there is a western branch, which runs north, chiefly along the eastern border of Congo (Kinshasa); this branch is marked by a chain of lakes, including lakes Tanganyika, Kivu, Edward, and Albert (Mobutu). Lake Victoria does not lie in the Great Rift Valley but between its main and western branches. The Great Rift Valley ranges in elevation from c.1,300 ft (395 m) below sea level (the Dead Sea) to c.6,000 ft (1,830 m) above sea level in S Kenya. Erosion has concealed some sections, but in places, notably in Kenya, there are sheer cliffs several thousand feet high. The present configuration of the rift, which dates from the mid-Pleistocene epoch, is probably a result of a rifting process associated with thermal currents in the earth's mantle (see rift valley); there is evidence of earlier rift structures.

Golden Valley, village (1990 pop. 20,971), Hennepin co., SE Minn., a residential suburb adjacent to Minneapolis; inc. 1886. Transportation equipment, meat products, and machinery are produced, and there are research facilities.

Fountain Valley, city (1990 pop. 53,691), Orange co., S Calif.; inc. 1957. Chiefly residential, Fountain Valley also has diverse manufactures, including apparel, computer equipment, semiconductors, and medical equipment. A U.S. navy helicopter facility is there.

Fergana Valley or Ferghana Valley, region, 8,494 sq mi (22,000 sq km), divided among Uzbekistan, Tajikistan, and Kyrgyzstan. The Fergana Range (part of the Tian Shan system) rises in the northeast and the Pamir in the south. The narrow Khudjand Pass in the west has historically served as an invasion route into the valley. The Xinjiang region of China borders the valley in the southeast. The Fergana Valley, consisting partly of the very fertile Karakalpak steppe and partly of desert land, is drained by the Syr Darya River and by numerous mountain streams, which are fed by snowfields and glaciers in the mountains. A dense irrigation network is linked by the Great Fergana and South Fergana canals. Major cities of the valley include Fergana, Kokand, Andijan, and Namangan, in Uzbekistan; Khudjand, in Tajikistan; and Osh, in Kyrgyzstan; many of them are connected by a circular rail line, which also has spurs serving the mining settlements on the valley's periphery.

The Fergana Valley is one of Central Asia's most densely populated agricultural and industrial areas. Cotton fields, orchards, vineyards, walnut groves, and mulberry tree plantations (for silk) cover the region, which is one of the world's oldest cultivated areas. Along the fringes of the valley are deposits of oil, natural gas, and iron ore. The region's natural resources contributed to the industrialization of all Soviet Central Asia. Cotton and silk milling and the manufacture of chemicals and cement are among the valley's important industries.

According to ancient Chinese sources, the Fergana Valley was a major center of Central Asia as early as the 4th cent. B.C. The introduction of silk raising from China, the development of cotton cultivation, and its favorable location astride the silk route between China and the Mediterranean stimulated the valley's growth. The Arabs, following the path of earlier invaders, occupied the valley in the 8th cent. and introduced Islam. The region was held in the 9th and 10th cent. by the Persian Samanid dynasty, in the 12th cent. by the Seljuk Turks of Khwarazm, and in the 14th cent. by the Mongols under Jenghiz Khan. The valley later belonged to the empire of Timur and his successors, the Timurids.

Early in the 16th cent., it was overrun by the Uzbeks, who established the khanate of Kokand. The opening of the sea route to East Asia around that time led to the decline of the prosperous caravan trade through the valley. Russian conquest of the Fergana Valley was completed in 1876; the region was then made part of a much larger unit called Fergana, which was a province of Russian Turkistan. During the Russian civil war, the valley was the center of the anti-Bolshevik Autonomous Turkistan Government, with Kokand as its capital. The crowded conditions in the valley contributed to ethnic violence in 1989-90, and Fergana has been one of the hot spots of post-USSR Central Asia.

Death Valley, SE Calif. and SW Nev., a deep, arid basin, 140 mi (225 km) long, bordered on the W by the Panamint Range and on the E by the Amargosa Range. In summer the valley has recorded some of the world's highest air temperatures (134°F;/57°C;) and ground temperatures (165°F;/74°C;). Less than 2 in. (5 cm) of rain falls annually; the small Amargosa River and Furnace Creek disappear into the sands. Salt and alkali flats, unique rock formations, and briny pools are found there. Badwater, in the south central part of Death Valley, is 282 ft (86 m) below sea level, the lowest point in the Americas; Telescope Peak, in the Panamint Range, is 11,049 ft (3,368 m) high. In spite of the harsh environment, a large variety of small animals and desert plants are found in Death Valley; they have attracted much scientific attention. Native Americans of Panamint descent, an offshoot of the Shoshone, are the only group ever to be self-subsisting in the region.

Death Valley was named by gold seekers who undertook to cross this desolate region in 1849 on their way to the California gold fields. The valley yielded gold and silver in the 1850s, and in the 1880s borax was discovered and taken out by mule-drawn wagons. The valley was much publicized by the American adventurer Walter Scott ("Death Valley Scotty"), and it remains a popular tourist attraction. Death Valley National Park, 3,367,628 acres (1,363,412 hectares), a protected region of Death Valley, was established as a national monument in 1933 and designated a national park in 1994. See also National Parks and Monuments (table).

Cumberland Valley, 75 mi (121 km) long and from 15 to 20 mi (24-32 km) wide, part of the great Appalachian valley, between the Potomac and Susquehanna rivers, W Md. and S Pa. It is a fertile farming area that is becoming urbanized. Chambersburg and Carlisle, Pa., and Hagerstown, Md., are in the valley.

Coachella Valley, arid region, SE Calif., N of the Salton Sea. Water is brought into the region by artesian wells and by the Coachella Canal (123 mi/198 km long), a branch of the All-American Canal built between 1938 and 1948; more than 100,000 acres (40,500 hectares) have been irrigated. 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. The tourist resort of Palm Springs is nearby.

Central Valley project, central Calif., long-term general scheme for the utilization of the water of the Sacramento River basin in the north for the benefit of the farmlands of the San Joaquin Valley in the south, undertaken by the U.S. Bureau of Reclamation in 1935. The program's concerns are flood control; improvement of navigation; the development of hydroelectric power, irrigation, and municipal and industrial water supply; protection of the Sacramento delta from seawater encroachment; and the propagation and preservation of fish and wildlife. Shasta and Keswick dams on the Sacramento River, and Friant Dam, on the San Joaquin River, were among the first units built. Canals, such as the Friant-Kern, the Madera, the Delta Cross Channel (which uses Sacramento water to fight soil salinity in the delta), and the Delta-Mendota, are used to transport water throughout the valley. Among the hydroelectric dams are San Luis, Spring Creek, Judge Francis Carr, and Auburn. Folsom Dam is one of the several units constructed in the valley by the U.S. Corps of Engineers.

Central Valley, great trough of central Calif., c.450 mi (720 km) long and c.50 mi (80 km) wide, between the Sierra Nevada and the Coast Ranges. The Sacramento and San Joaquin rivers drain much of the valley before converging in a huge delta and flowing into San Francisco Bay; the delta is California's leading truck-farming and horticultural area. The Central Valley is California's agricultural heartland, although its urban and suburban areas have expanded dramatically since the 1970s. With its long growing season and fertile soil, the valley has the largest single concentration of fruit and nut farms and vineyards in the United States; cotton, grain, and vegetables are also grown. Precipitation ranges from 30 in. (76 cm) in the north to 6 in. (15.2 cm) in the south. Two thirds of the valley's agricultural land is in the south, while two thirds of its water is in the north. The Central Valley project sought to address this problem by bringing water from the Sacramento basin in the north into the San Joaquin Valley in the south, where Fresno and Tulare counties are the two leading U.S. agricultural counties. The dry, alkaline Tulare Lake basin in the extreme south is almost totally unsuitable for irrigation. Oil extraction and refining and petrochemical production are also important in the region. The Central Valley was seen by Spanish explorers in the 1500s but remained virtually uninhabited until the 1849 California gold rush. Irrigation was introduced in the 1880s.

Castro Valley, uninc. city (1990 pop. 48,619), Alameda co., W Calif., near San Francisco Bay. Chiefly residential, it also has light industries.

Barossa Valley, region of South Australia, S Australia. A major area of wine production 40 mi (64 km) NE of Adelaide, the valley was named by Colonel William Light for the British victory over the French in the Battle of Barossa (1811; now Barrosa), Spain, in which he fought.

Elongate depression of the Earth's surface. Valleys are commonly drained by rivers and may be in a relatively flat plain or between ranges of hills or mountains. Valleys formed by rivers and slope denudation are typically V-shaped; those formerly occupied by glaciers are characteristically U-shaped. Valley evolution is controlled mainly by climate and rock type. Very narrow, deep valleys cut in resistant rock and having steep, almost vertical sides are called canyons. Smaller valleys of similar appearance are called gorges.

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Elongated trough formed by the subsidence of a segment of the Earth's crust between dip-slip, or normal, faults. Rift valleys are usually narrow and long and have a relatively flat floor. The sides drop away steeply in steps and terraces. Rift valleys are found on the continents and along the crests of oceanic ridges. They occur where two plates that make up the Earth's surface are separating (see plate tectonics). Submarine rift valleys are usually centres of seafloor spreading, where magma wells up from the mantle. The most extensive continental rift valleys are those of the East African Rift System; other notable examples include Russia's Baikal Rift Valley and Germany's Rhine Rift Valley.

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Fragrant perennial herb and sole species (Convallaria majalis) of the genus Convallaria (lily family), native to Eurasia and eastern North America. White, bell-shaped flowers droop in a row from one side of a leafless stalk, which bears usually two glossy leaves at its base. The fruit is a single red berry. Lily of the valley is cultivated in shaded garden areas in many temperate parts of the world.

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Volcanic region, southern Alaska, U.S. Located in Katmai National Park and Preserve, the valley covers 56 sq mi (145 sq km). It was created in 1912 when the eruption of the Novarupta and Mount Katmai volcanoes covered the valley in a flow of lava. When an expedition visited the site in 1916, it discovered tens of thousands of fissures known as fumaroles spouting smoke, gas, and steam in the valley floor. The largest was 150 ft (46 m) in diameter; some had temperatures as high as 1,200 °F (649 °C). About 60 years later there were fewer than 12 fumaroles left. In the 1960s U.S. astronauts used the scarred region to train for Moon landings.

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U.S. government agency established in 1933 to control floods, improve navigation, and generate electrical power along the Tennessee River and its tributaries. The TVA is a public corporation governed by a board of directors. It has jurisdiction over the entire basin of the river, which covers parts of seven states: Alabama, Georgia, Kentucky, Mississippi, North Carolina, Tennessee, and Virginia. Created by Congress as one of the major public-works projects of the New Deal, the TVA built a system of dams to control the region's chronic flooding, deepened the channel to improve navigation, and encouraged the development of port facilities along the river. The projects greatly increased traffic on the river and provided cheap electricity, spurring the industrial development of what had been a chronically depressed regional economy. Seealso Public Works Administration.

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Valley, eastern California, U.S. Squaw Valley is located in the Sierra Nevada range on the eastern slope of Squaw Peak, northwest of Lake Tahoe. A world-famous winter sports area, it has ice-skating facilities, ski lifts, and trails, and it was the site of the 1960 Winter Olympic Games.

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Industrial region, west-central California. Roughly bounded by San Francisco Bay on the north, the Santa Cruz Mountains on the west, and the Diablo Range on the east, it takes its (unofficial) name from the extensive use of silicon in the region's electronics industries. The U.S. government invested heavily in the region's industry following World War II. A second economic surge occurred with the proliferation of personal computers in the 1980s, and a third surge followed the growth of the Internet in the 1990s.

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National park, northwestern Alaska, U.S. Located north of the Arctic Circle, it was made a national monument in 1978 and a national park in 1980. Occupying an area of 1,750,421 acres (708,370 hectares), it preserves the Kobuk River valley, including the Kobuk and Salmon rivers, forest lands, and the Great Kobuk Sand Dunes. Archaeological sites reveal more than 10,000 years of human habitation. It protects caribou migration routes; other wildlife include grizzly and black bears, foxes, moose, and wolves.

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(circa 2500–circa 1700 BC) Earliest known urban culture of the Indian subcontinent and the most extensive of the world's three earliest civilizations. It stretched from near the present-day Iran-Pakistan border on the Arabian Sea in the west to near Delhi in the east, and 500 mi (800 km) to the south and 1,000 mi (1,600 km) to the northeast. It is known to have included two large cities, Harappa and Mohenjo Daro (in what is now Pakistan), whose large size suggests centralization in two large states or one state with two capitals. Alternatively, Harappa may have succeeded Mohenjo Daro. It was a literate civilization; the language has been tentatively identified as Dravidian. Wheat and barley were grown, many animals (including cats, dogs, and cattle) were domesticated, and cotton was cultivated. The best-known artifacts are seals depicting real and imaginary animals. How and when the civilization came to an end is unclear; Mohenjo Daro was attacked and destroyed in the mid-2nd millennium BC, but in the south there was continuity between the Indus civilization and the Copper Age civilizations of central and western India.

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Valley extending from southeastern California, U.S., to Mexico. It forms part of the Colorado Desert. Intensive irrigation began in 1901 with the opening of the Imperial Canal, which diverted water from the Colorado River. Floodwaters in 1905–07 destroyed the irrigation channels and created the Salton Sea. The valley is now watered by the Hoover Dam and the All-American Canal. With 3,000 mi (4,800 km) of irrigation canals, it contains 500,000 acres (200,000 hectares) of cultivated land.

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Norwegian Gudbrandsdalen

Valley, south-central Norway. It extends about 140 mi (225 km) above Lake Mjøsa and Lillehammer. It was the scene of severe fighting in World War II in which the Norwegians and British attempted to hold off a German invasion. It is the setting for Henrik Ibsen's play Peer Gynt.

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or Fergana Basin

Large valley, western Central Asia. It is mainly in eastern Uzbekistan and partly in Tajikistan and Kyrgyzstan and is situated between the Tien Shan system and the smaller Gissar and Alay ranges. It has an area of 8,500 sq mi (22,000 sq km). One of the most densely populated areas of Central Asia, it is a major producer of cotton, fruit, and raw silk. Among the mineral deposits exploited are coal, petroleum, and mercury. It was conquered by the Arabs (8th century AD), Genghis Khan (13th century), and Timur (14th century). The khans of Kokand (see Qoaynqon) ruled it from the late 18th century until it was absorbed by the Russian Empire in 1876.

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Valley, southeastern California, U.S. The lowest, hottest, driest portion of North America, it is about 140 mi (225 km) long and 5–15 mi (8–24 km) wide. The Amargosa River flows into it from the south and contains a small pool, Badwater, near which is the lowest point in North America at 282 ft (86 m) below sea level. Death Valley was formerly an obstacle to pioneer settlers (hence its name); it later was a centre of borax mining. Declared a national monument in 1933, it was made a national park in 1994; the park covers 5,269 sq mi (13,648 sq km) and extends into Nevada.

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Valley, southern California, U.S. Part of the Colorado Desert, the 15-mi- (24-km-) wide valley stretches 45 mi (72 km) between the Little San Bernardino Mountains and the San Jacinto and Santa Rosa mountains. A productive agricultural region, it also has popular desert resorts, including Palm Springs.

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Spanish Valle Central

Valley, Chile. Located in central Chile between the Western Cordillera of the Andes Mountains and the coastal range, it extends about 400 mi (650 km) from the Chacabuco Range in the north to the Bío-Bío River in the south. The agricultural heartland of Chile, it was the original centre of European colonization beginning in the mid-1500s, and it continues to be home to most Chileans. Santiago is at its northern end.

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