Maybe I’m missing something. The Rio Grande can be walked across in most places, right? Unless there is a flood stage all at once.
Here’s a link to photos and travelogue in the Big Bend Park. Pretty evident the “Natural barriers, such as the Rio Grande river, already make illegal crossings more difficult in the region than in other segments of the border, Nextgov reports”..sounds like a lot of BS. At least what is shown in these photos and the blog comments, not very deep, and a porous border as a result.
Link: http://www.terragalleria.com/blog/2012/09/05/big-bend-national-park-rio-grande-river/