An example for this is the East Matagorda Bay. Bar-built estuaries are also found in The Netherlands. Estuaries found in North Carolina are also the examples of bar-built estuaries. for example Albemarle Sound and Pamlico Sound.
Bar-built estuaries are semi-isolated from ocean waters through the barrier beaches found between estuaries and oceans. Barrier spits and barrier islands are located between estuaries and oceans. As barrier beaches get formed they partially encircle the estuary allowing only small inlets to allow contacts between estuaries and ocean waters. Bar-built estuaries usually get formed over gently sloping plains placed along tectonically stable boundaries of marginal sea coasts and continents. The barrier beaches that encircle bar-built estuaries are formed in numerous ways. Wave action causes the formation of offshore bars. Here, the sand from the seafloor gets accumulated in extended bars parallel to the shoreline. This forms barrier beaches. Reformation of sediment discharge from rivers through current, wave, and wind action causes the formation of barrier beaches. Mainland beach ridges get engulfed because of the rise in sea level. This led to the breaking of the ridges and flooding of the coastal lowlands. Shallow lagoons get formed as a result. This contributes to the formation of barrier beaches. Extension of barrier spits through the erosion of headlands also form barrier beaches. Barrier beaches get created in shallow water. They are mostly parallel to the shoreline. This leads to the formation of long narrow estuaries. Water depth of these estuaries is between 5 m and 10 m. Barnegat Bay, New Jersey, Pamlico Sound, North Carolina and Laguna Madre, Texas are some of the examples of bar-built estuaries.
Scientists have made use of variety of criteria to classify estuaries. Previously they used to classify estuaries based on the rate of fresh water, evaporation.