These are classic boom-bust markets.  

Biggest questions seems to be whether a floodway property can be improved or repurposed to something that can be converted to an income generating property. 

This is a classic example of an advance fee loan scam.  

I know here in Houston there are neighborhoods that are being repurposed by developers which means the high value is now the value of the land only, and not the shack sitting on it.Developers will tear the house down and build high end buildings, homes, MFH, commercial or whatever.Drive the neighborhood and see what is going on.

You made a classic mistake you over improved for the neighborhood..So I agree with the OP  people that are looking for owner finance deals are the one's that will over look some of these issues to get into a nice new home.Although sounds like you have a boat load of capital tied up in the home.Either that or your just going to have to do the falling knife syndrome and ride it down until someone see's value and will pay you in full for it.Other thing you could do is move into it...

It might just be the classic sell high/buy low opportunity you're looking for.  

Classic examples of fiduciaries are trustees, executors, andguardians.

@Terrell Sapp While it is often used for scams, this seems like a classic legit case for adverse possession.

That doesn't even meet the classical 1% rule of thumb, which I think it too optimistic. 

This will have an impact on pricing pressure, since demand is higher than supply, classic pricing mechanism at work.