Potent potential

River basins provide water, food, energy and biodiversity -- all things necessary for life. But Cook said these are often used inefficiently, especially water.

“If you look at the total amount of water going into river basins and the total amount of food coming out of river basins, the conversion ratio is pretty small, pretty low. And certainly in the African basins it was often 10 percent or even less of capacity. So, there immediately you can see that there’s a huge potential to actually satisfy future food demands without necessarily compromising even more scarce water supplies,” he said.

The river basin is much more than just the channel of water and adjacent land. Cook said the whole landscape should be included.

“Often when people think of river basins they only think what happens once the water actually gets into the channel. But certainly in African basins often the proportion of water that gets into the channel, that is what’s called blue water, is a fraction of the total water going through the river basin system,” he said.

A river basin has two types of water.

“Blue water is water, such as irrigation water, that goes into the river channel and is taken out or put in ponds or lakes or what have you. It’s water that you can see. But the vast majority of water is what’s called green water, which is rainfall actually. It falls on landscapes. It’s used to produce food. It never actually gets into the river channel, but it’s really important. And it’s the major part of the total water balance in river basins,” he said.