Sounds like adverse possession to me and the city is SOL, but government is the greediest, most corrupt and murderous force on Earth, so good luck with that.
Most of us think we have more land then we do. The first couple feet are easement that any utility company can use. And it can be a company you don’t use. Spectrum came and put lines under my driveway and lawn because the neighbors wanted that crappy service when I have Comcast. I did my best to stop them but it’s unfortunately legal.
Adverse possession might not apply to claims against the government. Maybe the doctrine of settled boundaries?