Does it pass under a bank?
Doubtful.
I’m close to a very large river. I’d say it goes to the river. or did at one time. But since the city claims its not there, I’d say it’s capped at the river somewhere, and capped somewhere up the hill in the city somewhere.
come to think of it, I can remember twice in the last 25 years the street up the hill has collapsed into a sinkhole and had to be repaired. I bet it’s the same tunnel. The tunnel may even be half filled in by now. I haven’t looked down that manhole in 20 years. I bet everytime they fill in the sinkhole and repave, the fill dirt washes down the tunnel a little more and the street caves in again.