How did Mesopotamians deal with flooding?

The climate of ancient Mesopotamia was hot and dry, with thin, sandy soil that was unsuitable for growing crops. The area saw very little rainfall, so the people of the region depended on the Tigris and Euphrates rivers for fresh water. They depended particularly on the rivers' annual floods, which covered the land with silt from the riverbeds. The silt made the soil rich and moist, able to support crops and livestock in such quantities that an entire civilization arose in what was known as the Fertile Crescent.
Unfortunately, the floods could also be destructive. Too much water drowned the crops and created swamps which bred disease. Mesopotamian architecture was built of mud bricks, which the floods wore down. The Mesopotamians needed the water and silt the floods brought, but they had to control the pace at which the rivers distributed these things. They began by building reservoir basins for the annual overflow to run into, and levees to hold the waters back. Over time, they combined these approaches with an extensive network of canals and arrived at an ingenious solution: irrigation. Irrigation allowed the people to draw water from the rivers year-round, enabling them to produce significantly more crops. More crops supported more livestock and people, and the Mesopotamian civilization flourished. When the floods came, the canals broke the force of the floodwaters into thousands of smaller channels, mitigating the destructive effects of the floods and maximizing the benefits they brought to the land.
http://www.palmbeach.k12.fl.us/eagleslandingms/MesopotamiaAgriculture.pdf