Mystery on the eastern bridge

A recent contact, a bridge engineer, noticed two features on this bridge. Called ‘cutwaters’, they are shaped to spread the force of water hitting the bridge so protecting  it.  Apparently, unknown locally on single span bridges, they are a mystery, especially being situated on the opposite side of the bridge to the flow of the river!
These ‘buttresses’ could be to support an unstable bridge. Added later, this might indicate this was the first bridge to be built, or the foundations had a problem. Still, it’s a puzzle, as the other two don’t have them.