As the bridge reforms, each piece will pass through the river below creating a SPLASH and leaving WATER DROPS on each piece.
Save the image and use it as a new Particles object.
Set the particles up with these properties
Duplicate the WaterDrops so that there is one particle for each bridge piece.
Attach them to each bridge piece as a Hierarchy Element of the Scene Graph
Now place the particles near the bottom-middle of each bridge piece.