How come you need to add C++ to get effect working? You shouldn’t need anything more than a Material/MaterialFuctions to implement a system like (a blueprint might help, but it’s not necessary).
I was also looking for ways to make the water stream down the users camera view, using masks, gradients, Panners and normal maps should work in case. I also have one that I will be adding to my community project soon so that when the player goes from underwater to above water, I get some streams of flowing water (and water droplets) that occur for a a few seconds before fading out.
If you absolutely need it, then add a tutorial to show your end users how to set it up should work! 