Conforming water in Bryce is difficult to say the least. Not to mention the increased render time.

I've had fair luck using Amorphium pro to create OBJ's that have softer bio style shape, I've also struggled with painting terrain/height maps to create waterfalls.

So far, the best luck I've had for water is in 2D/Post. You can use a combination of Brushes and the Photoshop Liquify tool to accomplish some decent water.

Let me know if you're interested in 2D Manip. I'll try to find some decent brushes and give you some pointers.

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Ockham's razor- It's that simple