Be careful with ANY mapping, especially before you verify it, but I know of one lake in SC that Cmaps shows being 20-24ft deep, that's actually several acres of flats with stumps in it, that can even be seen via google earth/maps. I've alerted them about a year ago, but no change. Not that Im aware of anyway. I don't have a subscription to it, but use their web ap, and it's been down a while since their security breach a few weeks ago.