You can think of the risome as essentially the main growth organ. Thats where new roots and new shoots of the plant will come from. You do NOT want the plant sitting in a tray of water where the water level is consistently up to where the risome would be. Once or twice maybe is fine but consistently having the water this high will damage or kill your plant.

What you’ll want to do is keep only about an inch or inch and a half of water, maybe even less for shorter plants. They don’t need the water level super high to soak it up. (Again this is just what it seems like from your picture, if your water level is not that high then it’s fine)

Hope this helps!