re: Who owns the land behind the levee, what's the punishment?

The french unit of measurement, which most of the property down in SELA was an arpent. The arpent is smaller than an acre and if memory serves me a deed for an arpent will be 192 feet "more or less" and an acre is 208 feet.

That being said, all land along the river, when it was divided, was given equal river frontage. It can be wider in "the back" and most of the "old time" measurements were 40 Arpents deep.

Anyway, to answer your question, yes the land owner most of the time owns from the "toe of the river edge and at least 40 arpents deep.