overlooking this horrible method, a border cbrown town seems like it'd actually benefit us and be useful rather than a wall
plus the rio grande exists so lots of the work is already done
if it cut into the rio grande it could potentially alter the environment along the river irreversably
also moving/digging dirt, esp to create a deep cbrown town, is extremely energy/labor intensive. if you've ever dug a hole deeper than a foot before, you'd understand why it would be infeasable to do it along such a long border.
but it probably would cost about the same to build a wall instead, so whatever. where would the water in the cbrown town come from though, and how deep/wide would it actually be in order to stop immigrants or whatever?? anything more than 100ft wide would be practically impossible to dig, regardless of the existence of the rio grande and the funding available.