This isn't an environmental disaster like global warming funding. And by the way - when Trump zeros out the $22 billion per year the US flashes down the toilet funding the warmunist religion Trump will have paid for the wall and then some in less than one year. Let alone terminating the waste from subsidizing renewable energy, and terminating subsidies to renewable energy companies like Solyndra.
Putting a wall in the middle of the frickin Southwest desert is not an environment disaster no matter how many liars say it is. From El Paso to Box Canyon Amistad in Texas looks pretty doable. Where the Rio Grande is a significant influence will take some clever engineering (or creative thinking).
Anyone who has actually flow over the southwest knows that it is pretty brown.
The Rio Grande is a bit of a challenge. We could just put land mines on the American side of the river. Or stock the Rio Grand with crocodiles and Piranha. I'm for anything that keeps illegals off US soil and I frankly don't care how it is done.
The wall through California is really where the attention should go. Putting a wall down the California border is not an environment disaster no matter how many liars say it is. I've actually crossed that border - I welcome factual opposing views, but don't expect any.
With environmental sensors embedded in the wall the border patrol can be notified of crossings.
In the event the wall is breached, given that is by definition an invasion, Apaches and A10s can be dispatched to deal with the miscreants.