I forgot you can't make walls near water

[The_Blode]

Or maybe i never really knew since i have always avoided settling close to water of any kind. I was making a nice little area next to a pond. My walls were going to do a little right angle thing around it. It's just not feasible to do anything with the area how i prepared it. Everywhere i was testing corner posts or whatever are just far enough from the water.
Built my first cornerpost and the first segment i tried to make gave me the water error.

I pocketed my good stuff and declaimed and put my character to bed for a while at least. This is such a great spot I had found. I'm just so sad. Damn.