According to this story, they’ve got the water in Zimbabwe, but they don’t have the electricity to pump it to the fields:

Rensen Gasela, a farmer in Midlands Province and former chief executive for cereals at the state-run Grain Marketing Board, told IRIN, “We have enough water in the dams but we do not have enough electricty supplies to irrigate the winter wheat, and many farmers have written off their winter crop, which was affected by moisture stress or inadquate water supply.”