I used to live in an area that had a canal through it with what seemed like a nice walking path alongside it. Those paths are there because many boats going down the canals were actually pulled by horses walking along the path.

Unfortunately, the path next to the canal in my area was full of groundhog holes, and it was nearly impossible to bike it or run it without riding or stepping in a 8 inch hole, which is just big enough to do real damage. And since it's a useless canal, there is nobody assigned to maintain it, which is why it's become a haven for groundhogs.