This is a childhood dream.
What would happen if pipes were installed (similar in principle to the Great Man-Made River, but for seawater) to continuously pump seawater into the Sahara desert.
Let's say that a precise desert location, with no known aquifer nor water table, was chosen to be an inner sea. And let's say that wildlife was negligible at that location. And that solar panels were installed to provide energy for the pumping of the water. And that the water was pumped at the surface of the Mediterranean sea and that precautions were taken not to greatly damage sea life.
How hard will it be to fill, say, a Nevada sized inner salty lake? And would that humidify the air enough that dew - falling to the ground each night - would somehow start a greening cycle?
What if a little mud was added to the water to precipitate into a bed that would retain the lake?
Is there any modification to this childish plan that would make it, at least, realizable?