Because those property owners acted as if the land was theirs in the intervening years, and because they were never told otherwise until recently, they essentially owned it through what’s known as adverse possession, states a letter submitted by Miller to the state.

The affected property — which constitutes small portions on the levee side of about 50 parcels — was thus entitled to compensation from the state, under eminent domain, if the flood board wanted to put in a new fence and access road.

State officials said they have not seen anything so far to suggest the questioned land was ever a "no man’s land."

http://www.appeal-democrat.com/news/property-122093-land-owners.html

The notion that simply because one uses land which is State owned for a long enough time will create adverse possession is not necessarily true. Each State has its own statutes and Court decision, frequently finding that the State is the owner even though it exercises no possessory right to property. For years it would be otherwise barred by the adverse possession statute. Each State follows its own process, so one must closely view how adverse possession against the governmental agency is treated in the owner’s respective State.