Examples are the Upper and Lower peninsulas of the U.S. state of Michigan, the Scandinavian Peninsula and the Niagara peninsula.[1][2][3][4] The surrounding water is usually understood to be continuous, though not necessarily named as a single body of water.
A vacuum breaker is an attachment commonly placed on a bibcock valve or toilet or urinal flush valve, that prevents water from being siphoned backward into the public drinking water system. This prevents contamination should the public drinking water system's pressure drop. vacuum breaker typically contains a plastic disc that is pressed forward by water supply pressure, and covers small vent holes.
With a pressure vacuum breaker, however, a drop in the pressure of the water enables the spring to snap the check valve shut. As soon as the water pressure drops, the check valve closes and backflow does not occur.n a pressure vacuum breaker, the water travels through a check valve and causes a poppet to raise up a guide into an air inlet. The air inlet also has a valve which ordinarily remains closed.