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Great Salt Lake, Utah
Photograph by Jim Richardson
Great Salt Lake's water level fluctuates dramatically due to seasonal shifts in inflow water volume and the rate of evaporation. The Utah lake is a closed basin with no outlet for water, so floods like those of the mid-1980s can be severe and destructive.
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Okavango Delta
Photograph by Bobby Haas
The seasonal flooding of Botswana's inland Okavango Delta can cover more than 10,000 square miles (26,000 square kilometers). The annual influx sustains a rich diversity of life, including herds of lechwe, or marsh antelope, who have adapted splayed hooves to help them walk on the muddy terrain created by the deluge.
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Thames Flood Barrier
Photograph by Tim Gartside/Alamy
Storm-driven tidal surges have caused England's Thames River to flood repeatedly, and occasionally catastrophically, throughout its history. To protect London, the government constructed the Thames Barrier, an engineering marvel that spans the river and uses six gargantuan moveable gates to block floodwaters before they reach the city. The gates lie flat on the bottom when not in use to facilitate river traffic.
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Aerial View
Photograph by David Edwards
Summer thunderstorms, like this one roiling over Alarcon Terrace, can turn the Grand Canyon's normally dry streambeds into seething torrents up to 50 feet (15 meters) deep. Such flash floods can quickly materialize miles away from where rainfall occurred, taking canyon hikers by surprise.
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Mississippi River Flooding
Photograph courtesy NASA
Before-and-after satellite images of the St. Louis, Missouri, region show the orderly path of the Mississippi River and its tributaries in 1991 and the catastrophic flooding that occurred when unusually heavy rains caused them to overflow their banks in 1993. High water along the Mississippi persisted that summer for nearly five months and caused hundreds of millions of dollars in damage.
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Venice, Italy
Photograph by Taylor Kennedy
Venice, Italy, is a city in perpetual flood. But sinking buildings, due to the extraction of groundwater, and rising sea levels have put this 1,300-year-old urban marvel in peril. High-water events—which used to afflict Venice fewer than ten times a year—now average nearly ten times a month. An ambitious system of floodgates to save the city is expected to be completed in 2012.
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Australia Flood
Photograph by Jason Edwards
Heavy seasonal rains, unable to penetrate the hard-baked ground of Australia's Simpson Desert, form shallow lakes in Witjira National Park. These so-called ephemeral ponds support an explosion of life, from waterbirds to wildflowers, then disappear as quickly as they came.
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Hurricane Damage
Photograph by Tyrone Turner
Most hurricane casualties come not from wind but from rain, waves, and surge—the vast mound of seawater that is pushed in front of the storm. The surge from Hurricane Katrina in August 2005 rose some 28 feet (8.5 meters), wiping out low-lying areas like Dauphin Island, Alabama, shown here.
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Atatürk Reservoir, Turkey
Photograph courtesy NASA
Dams are extremely disruptive to the surrounding landscape, but are a tried-and-true method of reducing downstream flooding. Throughout history, the Euphrates River (center-left) has flooded repeatedly, often even changing its course. But multiple dams, including the enormous Atatürk Reservoir and Dam in south-central Turkey (shown here), have largely tamed this critical Mesopotamian waterway.
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Amazon River
Photograph courtesy NASA
An astronaut's photo from 2008 shows the lower Amazon and several tributaries in flood. Each year, this mighty South American river swells with rain and meltwater from the Andes. At its highest, the Amazon will rise upwards of 30 feet (9 meters), submerging its entire floodplain, providing habitat for countless aquatic animals, and replenishing the landscape with nutrient-rich silt.
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Mekong River
Photograph by W.E. Garrett
Flooded rice fields like these are nothing new to the residents of Pakse, Laos. Farmers rely on the regular rise of the Mekong River to moisten the ground and fertilize their land. Unusually heavy rains in the summer of 2008, though, sent the river to its highest level in a century—at 45 feet (14 meters)—triggering deadly landslides and causing widespread damage in Laos and Vietnam.
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Monsoon Flooding
Photograph by Ami Vitale
When the annual monsoon rains come and send the Hooghly River over its banks, rickshas are the best way to get around Kolkata (Calcutta), India. Here, a drenched ricksha puller pauses for a photo in ankle-deep water near a market.
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Madagascar Estuary
Photograph courtesy NASA
Logging in Madagascar's rain forests and coastal mangroves has left the banks of the Betsiboka River highly vulnerable to erosion. Even minor rains send tons of rust-red soil into the river. Astronauts on the International Space Station said this shot, taken after Tropical Cyclone Gafilo roared through Madagascar in March 2004, looked like the Betsiboka estuary was "bleeding into the ocean."
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