Attaching a global trigger to a material.

I am currently implementing FMOD footsteps into UE4 based on the material the player is travelling across.

I have got the system working so that when the player enters a box trigger, wet footsteps will play. However, there is a lot of winding river sections to the map I am working on and so implementing triggers across all of these winding rivers seems like an unnecessary task.

Is there a way to apply a trigger so that when a player is stood on the water material (which is duplicated around all of the river sections), this triggers he variable which is used to begin water footsteps.

Did you tried physical materials?