This is a new design for floodgates (Swing vs. Lift), which are opened during Monsoon season, when whole trees can wash downstream and form dams on barriers.
From further back:
Below you can see from last Thursday (8 Oct 20), that they have passed the river itself (the dense treeline), and were nearing the pre-existing "short" (18 foot) bollards. That gap is just a few days work, at an average pace of 20 panels (160 feet) per day for a crew.
Outside of the riverbed itself, and additional run of smaller single swing gates were installed in the floodplain, for worst case flood years.
The foundations for a patrol road bridge over the high water mark can be seen. That will allow Border Patrol rapid mobility to respond year round.
You can bet that this new infrastructure will be bristling with detection technology - seen and unseen.