One rec.ponder caught a snake in her pond using a
minnow trap. Baited with a fish and the snake swam in
and couldn't get out. She left part of the trap above water.
Depending on the size of the snake you might have to modify
the opening.
Continued harassment might do the job.
otoh, I have no problem dispatching a poison snake who
won't leave.

We had a fellow who was bitten by a decapitated rattlesnake
head in our area.

k :-)