The photo of "the fence" in this article offers an idea of how the CBP might be able to utilize the National Guard units sent to the southern border.  Here's my idea:  have one of the local ranchers show the Guard units how to string barbed wire along the top 6 or 8 inches of the fence. Then about every 3 inches (above the barbed wire layers, upward) for at least a foot or more (upward), have them string electric fencing wire.  Believe me, if those people touch electric fencing just once it will send a message loud and clear.

http://jw.structure.email/corruption-chronicles/drugs-gangbangers-convicts-enter-u-s-via-mexico-as-media-focuses-on-shelter-accommodations

Granted, it's only a temporary solution until they figure out how to bypass that solution (they always figure out a way around anything we've tried so far) but it would help until a better solution comes along and it wouldn't cost an arm and a leg to do this.  I'll bet some of those ranchers would volunteer!