Fluid baking not following deformed mesh?

New to forum! I have searched every where and have not found the best solution and maybe asking the wrong question?

Trying to have a fluid simulation follow a deformed mesh that is animated.

I have a surface cube(obstacle) that has a boolean cut a valley in it and want the water to then follow the valley.

Like water erosion…

When i bake the fluid sim and watch the animation it sets on the surface cube (obstacle) as if it did not change?

Any suggestion , thanks for the help hope this makes some sense?

How to have water follow a deformed mesh?

That might be abetter way of wording it. Is this even possible in blender?