IMPERIAL VALLEY, CALIFORNIA, AUGUST 2009: Scenes from an artifical wetland filtration system designed to purify runoff water set in an agricultural area which traditionally uses water from the Colorado river distributed through a series of canals and irrigation channels, Imperial Valley, 6 August 2009. The Imperial Valley is a desert area which controversially uses three quarters of Californias allocated river water for agricultural purposes. The agricultural techniques have traditionally been flood and furrow which experts claim waste vast quanties of precious water. Imperial Valley farmers are looking at alternative techniques through which to conserve water supply. (Photo by Brent Stirton/Reportage for Getty Images.)