I understand that you are mentally unstable, but even if the city were to change the sewer route, that would not change the ownership of the land above the sewer system. At most, it creates an easement to allow the city to get to the pipes.

As to widening of streets, to the extent that any private property was taken, the owners are entitled to compensation. They can even challenge, in court, the amount of this award and present their own surveyors. It happens all the time. In fact, it happened when the streets were originally put down and then again when sidewalks were installed.