Irrigating a Desert with Sea Water

In recent months, I've been reading a lot about current environmental issues like desertification and rising sea levels.  These are such contrasting issues, don't you think so?  This got my imagination running again.   Remember my thoughts on garbage utilization and city master planning?    This is part economics & logistics, atmospheric science and irrigation.  So here's my wild thought.

Build an underground tunnel from the ocean to the desert.  Collect the water in plots very similar to salt beds.  You can probably use a solar pump to get the water from the trench connected to the tunnel to the beds.    In fact, make it these basic salt beds.  Then, cover the beds with a passive solar distillation set.  Basically you'll have slanting glass on top so that the condensation seeps into a central storage container. That water can then be used for irrigation purposes.

Why this method?  Normal water treatment is expensive so I say go for something passive and maximize the scorching sun. In fact, using a magnifying glass structure on the ceiling might help burn through the sea water.

To conserve water, the plants should be in a greenhouse that conserves moisture.  In effect, you'll have filtered sun in a high humidity environment.  And the salt beds?  Well they can be used as salt beds.  I couldn't find any salt usage for construction.  Salt sculptures? These two concepts together could also attract some tourism dollars.

Will this idea be commercially viable?  Perhaps.

For a while I was toying around with basic evaporation and hope that clouds will form on top of the desert, but that seems to be a long shot.  Just contain the water within the greenhouse.

I also thought about planting salt tolerant vegetation like mangroves but that didn't seem to be the ideal solution because salt basically retards the ability of plants to absorb water. This type of solution will be very limiting in terms of vegetation selection. 

On the side, this also effectively "enlarges" the ocean coverage which should increase overall water evaporation.  In turn, this increases fresh water production and somehow helps clean ocean sediments.  After all, we've been leaching so much nutrients to the water that its killing marine life.

What do you think?  Does the idea have a fighting chance?

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