Greater Farallones


Tidal Estuary

Tidal estuaries occur along coastlines, often in areas where one or more freshwater bodies flow into. The freshwater mixes with the salty seawater, creating brackish conditions. Estuaries such as Bolinas Lagoon, a 1,100 acre tidal estuary in Marin County, California at Greater Farallones National Marine Sanctuary, contain unique open water, mudflat, and marsh habitats that support a diverse population of terrestrial and aquatic flora and fauna. Invertebrates and juvenile fish seek refuge in the waters, while wading birds, such as herons and egrets, can be found foraging in the shallows and nesting in nearby trees.

Tidal estuary
Photo: Nick Zachar/NOAA