To my knowledge no official specs have been released; though given it's made on the Unity engine, rule of the thumb are they are fairly low. Though, the water probably creates a lot of CPU Load.
I'd say you need at least a decent Quad-Core Processor. I can run it on one of my PCs with an AMD FX-4130, and it's pretty low end at around 45-60FPS. As for GFX Card? I can't say for sure. Runs fine on an R7 260X with 2GB of VRAM. RAM in general could be an issue, again, due to the water. You should probably have at least 8GB of RAM.