Is it feasible to separate the Mediterranean from the rest of the world's oceans using dams?

In my world, Southern Europe, Northern Africa and all the territories surrounding the Mediterranean belong to a single empire.

The Emperor and his Council have decided that they are going to drain the entire Mediterranean Sea. They have of course read about the century-old Atlantropa plan, but they are going to do it with (real-world) 2016 technology.

They are a mighty empire and are willing to make this a massive project with a humongous amount of resources allocated to it. They are willing to spend decades if need be.

The motive for doing this is to gain more land-area.

They're planning to build a dam across the strait of Gibraltar to hold back the Atlantic.

The empire also controls all land around the Black Sea. They don't mind draining it. But if it presents big challenges, they may also consider simply building a second dam to hold the Black Sea back.

1. Is the Gibraltar dam feasible?
2. Will the Black Sea dam be needed?
3. Are any other dams needed to separate the Mediterranean from other oceans?
4. Are there any other significant challenges that might make it impossible to hold the Mediterranean separate from the world's oceans? (Serious challenges also solved are a bonus.)

No elements of fantasy or hand-waving are allowed. This needs to be explained in a scientifically sound way.

Do also note, however, that there are little or no political problems. The Emperor and his Council do control the entire region, and have no political problems with the plan. It's an extremely prosperous and resourceful empire, and there is no lack of political or public will.

Please note that while this is indeed similar to Atlantropa, it is not identical to Atlantropa. For example, the Empire intends to drain the whole Mediterranean, not just parts.

posted about 8 years ago

Revetahw says Reinstate Monica‭

1 reputation 3 0 0 0