Interesting, personal I think they should focus on filling Chott Al Djerid, it's not much above sea level, and as such a few hundred windmill can slowly pump sea water into it, in the east a canal can lead the brine to Chott Melrhir, Chott el Gharsah could be kept empty except for a canal to Melrhir, the increased humidity would transform Gharsah into an fresh water lake, while Djerid would be a saline lake and Melrhir a western version of the Dead Sea.
Gharsah could be used to irrigate the area around the lake.
Uh, Chott Al Djerid is at least 30 feet (10 meters) above sealevel, more
than is normally uplifted in the harvesting of salt. Plus a 30 mile canal
from the Mediterranean, minimum. And humidity would be mostly
unchanged, as the Sahara is decending air (extemely dry) and that air
leaves often in hours to hundreds of miles away, just like most deserts.
Chott el Gharsah is only about 15 miles long by 3 miles wide, and no
one lives or grows crops there. Curious why it would be important to
leave isolated. The town is well above sea level about 50 feet or more.
This thread has been dead for well over a year, but I posted some
rather questionable matters on elevation. The hump shown in the
1800's French map above does not show, but with the new url
topomapper lists it. The top is about 3 miles of 150 feet (about
50 meters). Only 18 feet and the water starts to cavitate? So
siphons will not work. This means a cut.
The Chott Al Djerid will very possibly be easy to dig, as it is salt.
Disolve it away. But for 30 miles (50 Km) at very least a loose
alluvium must be piled up to make a canal. Salt pans are normally
very simple 5 feet hydraulically sluiced dredgings, and salt now
is sold for very little money, especially raw salt.
Plus the Tunisians and Algerians are wary of the plan. Looks like
the Roman and other texts are incorrect that the inland lake was
connected to the sea in those days. 30 miles of an average 90
feet is a lot of earthquake uplift in 2,000 years for that region
(but not for Chile, as some mega tremors have done about that
in one shot), and drainage inward would seem unlikely to be
so much over such a wide expanse.
If anyone is serious about these plans, now you know.