Create local foam near a GameObject
To create foam on a water surface near a GameObject, follow these steps:
In the Hierarchy window, open the context menu (right-click) and select Water > Surface, then create a water surface.
In the Inspector window of the water surface, in the Water Decals section, enable Foam.
In the Hierarchy window, right-click a GameObject and select Water > Surface > Water Decal.
The new water decal is now a child of the GameObject.
In the Scene view, move the water decal close to the GameObject.
Move the GameObject along the water surface and notice how a trail of foam forms in its wake.