It's pretty simple really. You'll likely need to experiment with the camera angle. Certain angles will give you a better view of what's below the water's surface.

You'll probably want to reduce the reflection of the water in the transparency production and reflection production tabs.

Also, you'll most likely need to reduce the murkiness of the water in the transpareny production tab.

Be sure to experiment with preview renders and be patient.

What version of Vue are you using?

Charles