I heard a story on the Texas Standard radio show this morning about the razor wire and the buoys. Cliffs Notes:
The orange balls are connected to a fence of cables underneath that are attached to cement footings, so you can't swim under. As shown above, there is basically a giant circular saw blade in between each buoy so you can't safely go over.
The actual border runs down the middle of the Rio Grande, they are closer to the US bank, so they are technically on the US side. They are a violation of US-Mexico treaties however.
On the US side, in addition to the razor wire you see, there is razor wire hidden in the muck under the water. Anybody wading would get sliced. Which means its not intended to be a deterrent, its just simple cruelty. Remember also, other than in the Big Bend region, most of the land on the US border is private, or municipally owned, right up the middle of the river. Somebody or some municipality, is losing their access to the river.
Most of the atrocities you are hearing about (pushing migrants back into the water, denying aid to injured or pregnant migrants, etc) is being done by DPS or Texas Guardsmen. Border Patrol will take them into custody, give them water and first aid, and take them to a detention center for processing.
JFC, Abbot and Texas making Border Patrol the good guys.