The plans I saw were not simple. No, putting up a cow fence is all of useless. I agree. But a real fence, like some of the proposals, would be quite effective. And doable if we want to.
China built the great wall 3000 years ago. It worked well. I think we can do better. AND accommodate the river.
I brought this point up to someone here about a year ago.. and was told that “border security is more important than some cows getting a drink”.
The stupid burned so hot that I felt it on this end, so I didn’t pursue the matter.