They built an irrigation system containing canals,ditches,and gates. The system would redirect the flood water to the crops. The water picked up soil on the way down the mountain. That soil was used for growing crops.
Keeping records They invented the bulla. The bulla was a clay pouch with tokens inside. There were markings on the outside to show what type of tokens it contained. This kept records such as, how much does a person owe for a plow.