I'm curious about the city wall classification. If, in ancient times, a small section of the wall fell (analogous to an Eruv wire break), would the area typical

I'm curious about the city wall classification. If, in ancient times, a small section of the wall fell (analogous to an Eruv wire break), would the area typically contained by the wall no longer be considered a walled city/community? The article writes "When a group of rabbis in the ’80s took a boat around Manhattan to create a map, they realized that most of the wire was gone." and the other article [1] describes the condition of the wire as "intact on every Shabbat except one 2010 snowstorm" and worthy of a Twitter feed to check the weekly status. I don't imagine that a chipped stone on top of Jerusalem's wall in 600 BC would have made the walled city not walled for the purposes of an Eruv. Manhattan is an island, wouldn't it be enough for the community to declare the shoreline the border of the city? (Or maybe I'm trying to apply logic in a place where it's superseded by authority...) [1]: https://www.atlasobscura.com/articles/eruv-manhattan-invisible-wire-jewish-symbolic-religious-home https://www.atlasobscura.com/articles/eruv-manhattan-invisib...