How to disable refraction on water plane?

How would one go about disabling the refraction of the water plane.We want to keep the ripple and movement but our water is opaque anyway so there is no need to even have the refraction buffer written or having the calculations done.

is is as simple as commenting out some stuff in the hlsl shader or what. Just my opinion but I think that this is something that should be attached as a parameter of the water plane.