>The legal description on my property actually states 'to the top water mark.' Depending on flooding habits, my property could shift dramatically in either direction!

So, have you developed a habit to flood your property? :)

When I was about two years old, we lived some time in village Molin, built by German settlers, which was deserted when these were exiled after WWII, and repopulated by colonists from Bosnia and other mountainous areas. The village was built on lowlands, but the original inhabitants have built and maintained a system of canals, which kept it dry. The yards were paved with bricks. Some time in 1957 or so, the village had to be deserted. The montagnari couldn't understand the destructive power of water creeping from the soil, and never got around to learn how to maintain the canals. They grew up in mountains, where any water just flows further down. If one picked a brick from the pavement, there was a puddle under it. The houses, mostly made of adobe, started to crumble and fall. Very few people remember that the place ever existed.