cloud collector for the Sahara

when I started considering the idea of drawing the map of the geographical impact of a contrary spinning planet earth (if the earth span the opposite way) I focused my attention over the well known anomaly of the Himalayas mountains preventing India to became a complete desert as the Sahara and the Arabic which are on the same latitude.

starting from this deed I thought it was utopically possible to create an artificial barrier to stop clouds and humidity for desert regions as the western sahara coasts, for instance.
the big wall (5000m high!!) would be an horrifying destruction of all the ecosystem of northern Africa and a shocking environmental impact as well! besides it would be a very big danger for all the population and nature around in case of structural collapse of the building and, furthermore, it is technically impossible to build so far.
BUT these are not good reasons to stop imagining this awful solution as a functionally realizable system in order to achieve the task of a wetter Sahara coast-line!

can you imagine how horrible a huge 5 km tall wall crossing all western sahara regions north to south should be? a very huge disaster for the planet and a scaring structure to be seen from below...
anyway, the 5 km high wall would work as the Himalayas does for India, stopping the humidity coming from the Atlantic ocean and collecting the clouds in some season of the year provoking rain falls and the creation of huge rivers and so on.

this is a possible position of the wall even if I'm not sure if it's a good one!
maybe the eastern coast-line of the desert is a better place to catch the humid winds... (it depends of the air currents in that area) or possibly a east-west wall would work better than a north-south one.
anyway, that's not the point! just imagine! if it works naturally in Himalayas it can work artificially elsewhere!

possible position of the wall for the humidity recollection in western sahara.

so, this was the first idea:
stopping the clouds, provoking rain falls and also reducing the solar irradiation for the areas below the wall because the shadow of such a big barrier would stop the direct sun beams of a 40% (let's say).
as you can see the change for the region would be huge!

but even if this idea is just a utopic game for the imagination, the strong visual impact is too big to imagine even for me!! so I change my opinion about this crazy plan (even imagination has some ethical limits!).
Instead of a big wall, that's too much, maybe we could just use a system that already exists (in a very smaller scale) that is a fog-collector.
the humidity collector is a sort of simple net that literally catches the waters from the morning humid air and collect them into special reservoirs by mean of tubes .

so, what about building a structure (I mean, at least near the major cities and towns of the desert areas) that can do the same thing at a bigger scale?

we can imagine a 1000m high structure beyond the coasts of the cities of Western Sahara and Mauritania as a net filtering the clouds that generally pass above the dry country and that wind up evaporating by the heat.
the humidity of the clouds is now filtered and collected at a very big scale!
moreover the filter will block a bit the winds and the lower clouds as well, and it will also reduce the direct irradiation of the sun working as a solar screen for the town.

the impact would be less the before... and the advantages would be the same!
(I hope)

ok, but remember: this is just a utopia!
I really wouldn't like these kind of horrible structures would be built in reality!
please! just don't listen to what I said!!