I have been struggling with water for awhile in noggit3 and I am in the process of just giving up on blending it all together, but I am trying to figure out how to recreate the 'transition' from a lower opacity to a higher one that you see on Azeroth, pictured here ...

It goes from a low 0-20 opacity to upwards of 200. I can't seem to figure out how to recreate that transition in any way? Is it a setting? A toggle? Another program?