Millions in Kenya face starvation

CNN.com

What's up with Africa? How come they have starvation crises over and over again? Yes, I feel kind of sorry for them, but also it kind of wears thin if the same people need the same help again and again and again. I apologize for my ignorance, but I wonder why they don't have an irrigation system down there? They don't know what is a dam (like the Hoover Dam or the Three Gorges) which could store water and generate electricity to power their industries?