Ashley Cooper / Empty hydro canal during severe drought. This canal usually takes water to a hydro plant as part of the Tule River hydro system, California, USA, October 2014.

Ashley Cooper / Overspill, standing high and dry at the Hoover Dam on Lake Mead, following a four year long drought. Nevada, USA, September 2014.

Ashley Cooper / Intake towers for the hydro plant on the Hoover Dam, Lake Mead, Nevada, USA. The lake is at a very low level due to the four year long drought. September 2014.

Ashley Cooper / Lake Mead at a very low level due to the four year long drought. Lake Mead, Nevada, USA. September 2014.

Ashley Cooper / The Hoover Dam and Lake Mead hydro electric plant, which is at very low levels following a four year drought. Border of Nevada and Arizona, USA.

Ashley Cooper / The Hoover Dam and Lake Mead hydro electric plant, which is at very low levels following a four year drought. Border of Nevada and Arizona, USA.

Ashley Cooper / The Hoover Dam and Lake Mead hydro electric plant, which is at very low levels following a four year drought. Border of Nevada and Arizona, USA.

Ashley Cooper / A 700 Kw hydro pwer scheme being constructed on the slopes of Ben More on Mull, Scotland, UK.

Ashley Cooper / A 700 Kw hydro power plant being constructed on the slopes of Ben more, Isle of Mull, Scotland, UK. August 2014.

Ashley Cooper / At 152 Mw the Sloy Hydro Power Station is the largest hydro power station in the UK, Loch Lomond, Scotland, UK. August

Ashley Cooper / House with home made small scale hydro turbine to provide electricity, Isle of Eigg, Scotland, UK, May 2012.

Ashley Cooper / Sloy hydro power station on the shores of Loch Lomond, Scotland, UK. May 2012.