A jetty's a structure extending into a body of water, which protects a harbor or coastline from the effects of currents and tides. Coastal lagoons fronted by barrier spits typically have entrances that migrate over time. Here, the entrance has been fixed by jetty variety of structures used in river, dock, and maritime works which are generally carried out in pairs from river banks, or in continuation of river channels at their outlets into deep water; or out into docks, and outside their entran… (More on Jetty)