Luiz Claudio Marigo / Aerial view of Samuel hydroelectric dam and lake formed by the dam, west of Porto Velho city, Northern Rondônia State, Western Brazil.

Luiz Claudio Marigo / Aerial view of Sugar cane plantation and dam, Cerrado region, Northern Mato Grosso State, Western Brazil.

Jerry Monkman / A beaver flowage on the Isinglass River in Strafford, New Hampshire, USA

Jerry Monkman / Fly-fishing on the Moose River below the dam on Brassua Lake in Rockwood, Maine, USA. model released

Jerry Monkman / Fly-fishing in the early morning mist on the Androscoggin River just below the dam in Errol, New Hampshire, USA

Jerry Monkman / A fly-fisherman on the Lamprey River below Wiswall Dam, Durham, New Hampshire, USA

Jerry Monkman / A hydropower dam on the Androscoggin River, which provides power for the paper mill in Berlin, New Hampshire, USA

Jerry Monkman / A beaver dam in Woodman Brook, a tributary of the Lamprey River. Durham, New Hampshire, USA

Nick Upton / Eurasian beaver (Castor fiber) dams across drainage channel, Narew marshes, Poland

Igor Shpilenok / Aerial view of the landslide of June 3, 2007, which blocked part of Kamchatka's Valley of the Geysers, damning the Geyser River and creating a lake. This picture was taken on June 15, six days after t...

Igor Shpilenok / Aerial view of the Ranger stations after the landslide of June 3, 2007, which changed the face of the Valley of the Geysers, Kronotsky Zapovednik, Kamchatka, Far East Russia During the landslide of J...

Igor Shpilenok / The Geyser River turned lake, Kronotsky Zapovednik, Kamchatka, Far East Russia The Geyser River, which carved the canyon known as the Valley of the Geysers, turned into a lake after the landslide of...

Jean E. Roche / Villefort dam, Massif, Central France

Luciano Candisani / Itaipu Dam, the largest in the world, Parana River near Iguacu Waterfalls, Brazil

Luciano Candisani / Electricity pylons and power lines from Itaipu Dam, Brazil

Luciano Candisani / Machadinho Dam, small hydroelectic plant in Parana River, Brazil

Luciano Candisani / Electricity pylons and power lines from Itaipu Dam running through a wheat field, Brazil

Yva Momatiuk & John Eastcott / American Beaver (Castor canadensis) a semi-aquatic rodent swimming branches across calm pond behind beaver dam, fall evening, Denali National Park, Alaska

Nick Gordon / Aerial view of Balbina Hydro electric dam, 2400 sq kms of rainforest flooded, nr Manaus, Amazonia, Brazil

Jean E. Roche / Helicopter dropping sand sacks, dam breach of Rhone, Arles, Camargue, France, December 2003

Jean E. Roche / The first electric dam along the river Rhône, Morel, Switzerland

Michael Durham / American Beaver (Castor canadensis) building a dam at night, Mt Hood National Forest, Oregon

Tim Fitzharris / Beaver dam and pond surrounded by boreal forest with Mount Robson in background Mount Robson Provincial Park, British Columbia, Canada

Nick Gordon / Aerial view of Balbina Hydroelectric dam near Manaus, Brazil. It flooded 2400 sq km of rainforest when the dam was opened in 1982.

Ross Couper-Johnston / Aerial view of Parana river, before dam construction, Argentina / Paraguay border, South America

Steven David Miller / Lotusbird walking on lily pads {Irediparra gallinacea} Fogg Dam, Northern Territory, Australia

Willem Kolvoort / Dead rainforest tree on the "beach" of Lake Brokopondo, Surinam. Dam was built in 1964 and the rainforest flooded. In dry season some tree roots are exposed on the higher ground. 2003.

Willem Kolvoort / Flooded rainforest trees in Brokopondo power dam lake, Surinam. Dam was built in 1964 and the rainforest flooded. 2003.

Nick Gordon / Aerial view of Balbina Hydro Electric Dam near Manaus, Brazil. The formation of the dam flooded 2400 sq km of rainforest in the area.

Thomas Lazar / Sunrise over water at Turtle Flambeau Flowage (result of 1926 construction of dam to create reservoir) Wisconsin, USA

John Downer / Hoover dam and electrical power station (built in 1936) near Las Vegas, Arizona, USA

LYNN M. STONE / Beaver dam on lake, surrounded by autumnal woodlands, Glanville, New York, USA Captive.

Thomas Lazar / Sunrise over water at Turtle Flambeau Flowage (result of 1926 construction of dam to create reservoir) Wisconsin, USA

Chris Gomersall / Craig Goch reservoir and dam, Wales, UK

Dave Watts / Hydro-electric dam on Noguera river, Lerida, Spain

Richard Du Toit / The Jozini Dam, Kwa-Zulu-Natal, South Africa

Rob Tilley / Barker Dam, Joshua Tree National Park, California, USA

Jose B. Ruiz / View from Cenajo dam, Cenajo reservoir, Murcia, Spain.

Philippe Clement / American Beaver dam and den {Castor canadensis} Grand Teton NP, Wyoming, USA.

Philippe Clement / American Beaver dam {Castor canadensis} Grand Teton NP, Wyoming, USA.

JEFF FOOTT / Beaver (Castor canadensis) lodge, dam and pond, USA

Dietmar Nill / European beaver {Castor fiber} dam, Lettland / Latvia.

David Kjaer / American beaver dam {Castor canadensis} Grand Teton NP, Wyoming, USA

Philippe Clement / Dam constructed by American beaver {Castor canadensis} Grand Teton National Park, Wyoming, USA

Niall Benvie / Eurasian beaver dam {Castor fiber} Latvia

Sumio Harada / American Beaver (Castor canadensis) building dam, Rocky Mountains, North America

Sumio Harada / American Beaver (Castor canadensis) underwater view of dam, Rocky Mountains, North America

Gerry Ellis / Effluence from Bonneville Dam, Columbia River, Oregon

Gerry Ellis / Effluence from Bonneville Dam, Columbia River, Oregon

Gerry Ellis / Effluence from Bonneville Dam, Columbia River, Oregon

Jim Brandenburg / American Beaver (Castor canadensis) repairing dam, Minnesota

Patricio Robles Gil / Aerial view of dammed valley for reservoir, La Boca, Nuevo Leon, Mexico

Steven David Miller / Water lily flower {Nymphaea sp} Northern territory, Australia Fogg Dam CR, Arnheim highway

Jabruson / Trees killed by rising water, Theewaterskloof dam, Cape Peninsula, South Africa

Jean E. Roche / Water released from dam across Rhone river, Villabregues, Provence, France

Niall Benvie / Euroasian beaver {Castor fiber} dam. Nr Talsi Latvia Note scum on water behind & clear below

Juergen Freund / Hoover dam and electrical power plant near Las Vegas, Nevada, USA

Jose B. Ruiz / Beniarres dam, Benitadel mountain, Alicante, Spain, Europe.

Duncan Mcewan / Hydro electric power dam, Glen Finglas, Perthshire, Scotland, UK

Martin Gabriel / Lake Gordon (created 1972) low water mark shows flooded forest, created by dam in 1972. Southwest NP, Tasmanian wilderness World Heritage area. February 2002.

Steven David Miller / Lotusbird, aka Comb crested jacana, {Irediparra gallinacea} walking on lily pads, Fogg Dam, Northern Territory Australia

Martin Willis / Masked Finch (Poephila personata) carrying nest building material, Cumberland Dam, western Queensland, Australia

Martin Willis / Australian Kestrel (Falco cenchroides) roosting in aging bricks of chimney stack, Cumberland Dam, western Queensland, Australia

Onne van der Wal / Water dam, South Island, New Zealand.

Rick Tomlinson / Kariba Dam, Zimbabwe is located approximately halfway down the Zambezi River. The dam was surrounded by controversy, both environmentally and socially, it is an impressive monument to man's engineerin...

Richard Du Toit / Slime dam at mining operation, Gauteng, South Africa

Matthias Breiter / Abraham Lake created by Bighorn Dam on the North Saskatchewan River, Jasper National Park, Alberta, Canada

Christian Ziegler / Weir dam built to measure the rate of water flow, Lutz Creek, Barro Colorado Island, Panama

Norbert Wu / Glen Canyon Dam on the Colorado River which generates hydroelectric power and the Glen Canyon Bridge, Glen Canyon National Recreation Area, Arizona

Robert Thompson / Silent Valley and Ben Crom with dam in the background, Mourne Mountains, County Down, Northern Ireland, UK, February 1996

James Christensen / John Day Dam, Columbia River, Oregon

Vincent Grafhorst / Kittlitz's Plover (Charadrius pecuarius) wading, Gaborone Dam, Botswana

Vincent Grafhorst / Cape Wagtail (Motacilla capensis) walking, Gaborone Dam, Botswana

Pete Oxford / American Beaver (Castor canadensis) pond with dam and lodge, Grand Teton National Park, Wyoming

Pete Oxford / American Beaver (Castor canadensis) pond with dam and lodge, Grand Teton National Park, Wyoming

Pete Oxford / American Beaver (Castor canadensis) pond with dam and lodge, Grand Teton National Park, Wyoming

Jose B. Ruiz / Reservoir created by a dam at Tamajon, Guadalajara, Spain

Jose B. Ruiz / Reservoir created by a dam at Tamajon, Guadalajara, Spain

Jose B. Ruiz / Reservoir and dam at Tamajon, Guadalajara, Spain

Jose B. Ruiz / Reservoir created by a dam at Tamajon, Guadalajara, Spain

Theo Allofs / Bengal Tiger (Panthera tigris tigris) lying on dam wall cooling off during the heat of the afternoon in April during the dry season, India

Yva Momatiuk & John Eastcott / American Beaver (Castor canadensis) ponds created by the rodents building dams and raising levels of existing glacial kettle ponds, in colorful autumn tundra, Denali National Park, Alaska

Nature Production / American beaver {Castor canadensis} building dam, Denali NP, Alaska, USA, September 1990

Nature Production / Dam build by American beaver {Castor canadensis} Denali NP, Alaska, USA, September 1990

Yva Momatiuk & John Eastcott / American Beaver (Castor canadensis) a semi-aquatic rodent swimming across tundra pond behind beaver dam, with colorful reflections of fall tundra and vegetation on water ripples created by its passage...

Yva Momatiuk & John Eastcott / American Beaver (Castor canadensis) juvenile swimming in tundra pond behind beaver dam, surrounded by brilliant reflections of fall trees and grasses, evening, Denali National Park, Alaska

Claus Meyer / Animal rescue feeding small mammal, Balbina Dam Wildlife Rescue, Amazon, Brazil

Michael & Patricia Fogden / Lake Pedder, Southwest National Park, Tasmania, Australia

Jean E. Roche / Marsh vegetation at edge of reservoir created by Naussac dam. Haut allier France

Jean E. Roche / Bazacle dam Toulouse Haute- Garonne Languedoc France. Obstacle to Shad migration

Jean E. Roche / Water released from dam across Rhone river Villabregues Provence France