Ashley Cooper / The Iznajar hydro electric power station near Antequera in Andalucia, Spain. June 2011.

Alan Williams / Weir at the top of Rhaeadr Mawddach waterfall, part of hydroelectric electricity generation system showing outlet lower left Afon, Mawddach, Coed y Brenin Forest, near Dolgellau Snowdonia National Par...

David Kjaer / Almendra hydroelectric dam, also known as the Villarino Dam, on the Rio Tormes, Salamanca, Spain. June.

Juergen Freund / Brolga cranes (Grus rubicunda) in field as it is irrigated, Mareeba, Queensland,Australia.

Pete Oxford / Fishing boats in the Hope canal, an irrigation canal in East Demerara Water Conservancy, coastal Guyana, South America

Pete Oxford / Hope canal, an irrigation canal in East Demerara Water Conservancy (for sugar cane and rice production) coastal area of Guyana, South America

Pete Oxford / Hope canal, an irrigation canal in East Demerara Water Conservancy (for sugar cane and rice production) coastal area of Guyana, South America

Pete Oxford / Aerial view of mixed agriculture fields of East Demerara Conservancy, east of Georgetown, Guyana, South America

Pete Oxford / Wetlands of Abari Swamps, Mahaica Miconi Abari, Guyana South America

Franco Banfi / Electrode providing current to the structure of bio-rock, method of enhancing the growth of corals and aquatic organisms, metal covering a wooden boat wreck, Desa Pemuteran, Bali Island, Indonesia, Pa...

Franco Banfi / Power supply on the beach to provide current to the structure of bio-rock, a method of enhancing the growth of corals and aquatic organisms, Karang Lestari Pemuteran project, Desa Pemuteran, Bali Isla...

Franco Banfi / Cables connecting current from the power supply on the beach to the structure of bio-rock, a method of enhancing the growth of corals and aquatic organisms. Karang Lestari Pemuteran project, Desa Pemu...