A cool idea, but we’ll need water to function in a realistic volume-based way before these can work. Looking at the videos we’ve been offered so far, water seems to just fill any adjacent space without actually spreading out–it’s essentially creating water out of nothing.
If locks get added before water realistically floods out without being infinite, we could accidentally flood our entire world (up to the initial Y-height of the starting water). There was issues with this regarding liquids in the basic, more primitive versions of Minecraft:
(Apologies for the obnoxious music in the video, but this was as easy example to find)
Although, locks could be an early way to get water to higher elevations. And let’s be honest, flooding a world in Stonehearth would be pretty fun to try.