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.
Pressure type vacuum breakers â Installed in the pipe that supplies water to home sprinkler systems, a pressure type device constantly senses system pressure. If pressure in the system suddenly turns negative and drops below air pressure entering through an above-ground inlet, a check valve closes to prevent backflow.