The existing water system in Unreal Engine was too slow for me and had many bugs, which barely made it work, if at all. So I got rid of it, used some of the existing shader functions as reference, and made my own that runs much faster and gives me more control over what I want to do with it. I have access to the exact height of the water at a specified location, the direction of flow, and intensity of that flow.
Currently, river flows only blend nicely into lakes, but not oceans. Something I can try to remedy in the future, but for the time being it isn't an issue.
Ideally, adding a fully (heightmap based) dynamic water system similar to other games such as From Dust, would really expand gameplay possibilities while also looking good. A plugin for Unreal Engine exists for this, https://www.unrealengine.com/marketplace/en-US/product/fluid-flux. Hopefully future funding for the game can allow me to buy it and implement it.
Love you all,
Baron <3