coastallake

Coastallake refers to a body of water that is situated along a coastline and is separated from the open ocean by a coastal barrier such as a dune ridge, sand spit, or barrier island. These basins range from freshwater to brackish and may be ephemeral or persistent, depending on tidal connectivity and sediment dynamics.

Coastallakes typically form when coastal sediment, such as sand and silt, accumulates to build a barrier that encloses a natural depression or proglacial basin. Breaches or tidal inlets may periodically reconnect the lake to the sea, while others remain closed, making salinity more variable with rainfall and groundwater.

The water balance is controlled by rainfall, evaporation, river inflows, groundwater seepage, and tidal exchange through inlets. Inlets can flush saltwater in during high tides, raising salinity; dry seasons lower water levels.

Coastallakes host specialized communities: brackish or freshwater fish, crustaceans, aquatic plants, migratory and wading birds; margins provide habitat for reeds, rushes, and dune vegetation. They are sensitive to nutrient input and sedimentation.

Urban and agricultural development, dredging, or construction of bridges and channels can alter dynamics, affecting salinity, sedimentation, and biodiversity. Some coastallakes are protected as wetlands or part of reserve networks; monitoring programs track water quality, hydrology, and ecology.

The term is used in coastal geography to describe similar features worldwide, including lagoons and estuarine basins behind barrier systems, though local terminology varies.