A breachway is defined as the shore along a channel. Today the term is used to describe the whole area around where a channel meets the ocean. The Rhode Island coastline has many breachways on its map. Today's permanent breachways have rock jetties that line the sides of the channel to protect against erosion or closing of the waterway. The water channels usually lead to salt water ponds.
References
Breachway Wikipedia(Text) CC BY-SA