Often this has been the result of 'rescue excavation'.

A series of dams have been built across the rivers Tigris and Euphrates and their tributaries. The flood waters behind the dams have drowned large areas.

The water from a dam on the Tigris floods into the excavations as the archaeologist rescues the last find

Teams of archaeologists from as far afield as Britain and Japan joined Iraqi archaeologists to excavate sites before the area was flooded. They found evidence dating from the earliest farmers to modern times.

Although all the sites are now under water our knowledge of the region has been dramatically increased.