This 2006 SBS Australia documentary explains the discovery of vast advanced ancient cities in the Indus River Valley that existed at the same time as Mesopotamia (who they also traded with.)  Among the many topics it talks about, it explains how cities in the region made use of incredibly advanced engineering to capture and control seasonal flood water, and it explains how the cities were very productive and prosperous agricultural and manufacturing centers that created cotton fabrics, pottery, and bronze.  [Note: And see starting at about 10:30 for details about the elaborate systems that were created to harvest seasonal water.]