Floods cause disasters, but they can also be beneficial.
Whenever a river overflows its banks, it dumps sand, silt and debris that it has carried downstream onto the surrounding land. After the flood waters move away, the soil is more fertile, because of the organic matter and minerals in this material. Farmers since the time of the ancient Egyptians have known about the benefits that a flood can bring. Indeed, the ancient Egyptians planned their farming, and their lives, around the regular flooding of the Nile. They learned over time that, the higher the flood, the better that year's harvest would be.