Careful there: you might mess with the salt and mineral concentrations in the Mediterranean Sea. And, of course, there's lots of shipping through the straits of Gibraltar that you have to accommodate.

No problem withbsalinity in the most extreme varuants of this - you effectively let the whole Mediterranean Sea evapirate and only let in enough water to keep it this way, effectively making the whole scheme solar driven. That way you can also build multiple dams between island chains and get even more power, before the water eventually evaporates on the bottom most salt pan.

Also takes care of shipping. ;-) Although I guess you could build a near shore shipping channel, possibly filled with fresh water from rivers.

> No problem with salinity in the most extreme variants of this - you effectively let the whole Mediterranean Sea evaporate [...]

Well, then you still need to deal with the salt both as a onetime measure.

There's a far better option with the Qattara depression.