A water hammer mitigation system includes a branch connection with ends coupled to a main pipeline, where a first end connects at a surge point on the main pipeline and a second end fluidly connects to the main pipeline at a distal point. A bi-directional surge relief device is disposed on the branch connection, and is operable to move to a first open configuration to permit pipeline fluid within the main pipeline to flow through the branch connection when surge point pressure reaches a designated pressure. The device can also move to a second open configuration when surge point pressure reaches another designated pressure. The device is closeable when surge point pressure is between the designated pressures.