The valley the Turks flooded was in the interior of the country on the upper reaches of the Euphrates basin. They built a dam to provide power and water storage.
A recent documentary showed some of the marvelous finds in some old villas that were uncovered by hasty archeology even as the waters were creeping closer. They cut out the inlaid tile paintings from the floors and walls and sent them to a museum.
Just imagine how much more they could have found.