Engineers’ Dreams - Pushing the Limits: New Adventures in Engineering - page 159

of the Mediterranean to fall about forty inches per year over its one-million-square-mile expanse. In
order to be positioned across the strait so that its height nowhere exceeded about one thousand feet,
such a dam might have to be on the order of twenty miles in length. Once a dam was in place, in a
decade's time the level of the Mediterranean would drop more than thirty feet, and at this differen-
ce in elevation the water from the Atlantic could be sent through turbines to generate an enormous
amount of electricity. After a century, the 330-foot drop in water level would uncover ninety thou-
sand square miles of new land, resulting in the joining of the islands of Majorca and Minorca and
of Corsica and Sardinia.
Because of the undersea topography, the western part of the Mediterranean would not be ex-
pected to change much beyond one hundred years after the completion of a Gibraltar dam, and
Sorgel proposed that at that time two more dams be constructed, one between Italy and Sicily and
one between Sicily and Tunisia. With the western Mediterranean enclosed, its water level could be
maintained at 330 feet below present sea level. The eastern Mediterranean could be allowed to con-
tinue with a net loss of water for another century. Although the Mediterranean area would benefit by
about 220,000 square miles of new land and virtually unlimited quantities of hydroelectric power,
the lost water from the entire Mediterranean Sea would amount to adding possibly as much as three
feet to the level of the oceans worldwide.
Proposed dam across Strait of Gibraltar
The recognition that such a drastic rearrangement of the world's waters would be opposed by
many caused Sorgel to emphasize that the drop in the Mediterranean could be stopped at fifty feet.
This would mean that only a single-lock canal might suffice for getting oceangoing ships into and
out of the Mediterranean and would preserve the value of most existing harbors. Dropping the sea
level as much as one hundred feet would require additional locks at Gibraltar and at the Suez Canal,
and today's principal Mediterranean harbors would be far from the sea and thus useless. Even sup-
porters of Sorgel's plan, who saw its power-generating aspect as a distinct benefit, argued against