How can I get transform of LandscapeSplineActor

Hello guys,
I made a river using LandScapeSplineActor in Unreal.
However this river has a slope,
So I want to change the height of the water surface according to the spline transform.
Is there a way to get the transform(Location.Z) of the spline according to the character’s position in the LandScapeSplineActor?