I grew up in this town and there is a lake that is very easily crossed at night. You cannot build a fence over a lake.
We also used to own property along the Rio Grande, but sold it several years ago. As a kid we used to see illegals that had crossed over and they would run away after we would put a spotlight on them.
Times were different over 35 years ago.
“You cannot build a fence over a lake.”
Of course you can build a fence over a lake, it’s just much more economical to build the fence along the edge.