That is, the largest concentration of illegal immigrants, cross in a relatively few areas (San Diego, Yuma, parts of the Rio Grande) where there is already good access *from* the South.
The more of those areas that are blocked, the more two things happen:
1) Fewer people cross in areas that are harder and harder to get to.
2) The Border Patrol isn't stretched so thin, and has more manpower for the areas that are left.
“the largest concentration of illegal immigrants, cross in a relatively few areas (San Diego, Yuma, parts of the Rio Grande)”
San Diego is wrapping up its new Super Barrier - should be done in January (Primary is complete, Secondary about half done). This new funding is going to push them two miles further East up into the mountains, where there was nothing before.
Yuma is getting so much barrier, I am having a hard time tracking it all. Everything I recall seeing going in there is thirty feet tall, and I think at this point it may be completely continuous Trump-style Super Barrier through the whole of Yuma Sector - not just the urban area.
The Rio Grande Valley is looking at 95 new miles or more with the funding in hand - enough to substantially close it down (South of Falcon Lake to East of Brownsville), when agents and technology focus on the remaining few open miles. Five contracts have already been awarded there for about 32 miles. After the extended public comment period closes this month, we can expect a rain of contract awards to follow. Next year, the Valley should be a beehive of construction activity.