1. Over 1,000 miles of the border between Texas and Mexico is in the middle of the Rio Grande river. Building an actual, solid wall, down the middle of 1,000 miles of river bed would be virtually impossible.

2. The Rio Grande floods periodically, so the wall would have to stand up to floods. In 2010, the river rose 42 feet. Any wall not anchored deeply in bed rock would have washed away. Anchoring a 1,000 mile wall to bed rock would be prohibitively expensive.

3. The border goes right through the middle of dozens of reservoirs, some of which are more than 20 miles long. The largest is the Amistad Reservoir which is over 200 feet deep. Building a wall through it would require a 200 foot wall, 20 miles long, which would also be prohibitively expensive.

4. It is just as expensive to build the wall along the edge of these reservoirs. Fencing the American shore line would be almost impossible. The American shore line of the Amistad reservoir is over 120 miles long, with thousand of tiny inlets, coves and canyons.

5. The border also goes through Big Bend National Park. In Big Bend, the river wind through over 300 miles of canyons which are in some places more than 2,000 feet deep. Even if you could build a wall through 2,000 foot canyons, building it would destroy a national park, something the American people are not going to approve, even if you found a way to pay for it.

You can't just build along the edge of the canyon because side-canyons come in every few miles. The wall would have go up and down steep cliffs and block every side canyon, otherwise people will just walk from Mexico to the US through the side canyons. If you block the side the canyons, you are really just building new dams, which are very expensive, take decades to complete and have to be maintained and controlled just like any large dam.

6. If you build a wall away from the border to avoid the side canyons, inlets, coves, and meander of the of the River, you are giving thousand of square miles of land back to Mexico.

7. There are also many Native nations that have territories that lay between both countries and they will not approve of a wall that cuts them in half like Berlin!

8. There are too many legal hurdles it would have to pass first.