A baffle controls the normal process flow of liquid in basins of liquid treatment equipment, but releases uncontrolled flow of the liquid caused by events such as seismic events. Methods provide an unbent blank for making such baffle with a hinge member to facilitate the release of the uncontrolled flow. Further methods provide for mounting of the baffle for movement, urging the baffle for the control of the normal process flow, and allowing the uncontrolled flow to overcome the urging and release the uncontrolled flow. Baffle embodiments may be made from exemplary materials such as stainless steel, glass fiber reinforced polyester, pultruded FRP, and redwood.