The tide gates are kept open to allow for the rise and fall of saltwater in Straits Pond. This rise and fall occurs as a semi-diurnal tidal cycle with two episodes of high water and two episodes of low water with each lunar day. The tides allow for the exchange of Pond water into the Weir River estuary and out to Boston Harbor when draining towards low tide. New Boston Harbor and Weir River estuary water returns into the Pond with the incoming tide. The tide gates are set to trigger closed (when in automatic mode) when the water level reaches 3.55 ft NAVD88 in order to prevent flooding to lower-lying properties along the Pond.
The tide gates may be manually closed during low-mid water levels in the pond in advance of a predicted significant coastal storm event to provide added floodwater storage capacity of the Pond and improve flood protection to adjacent low-lying properties along the Pond.