(Courtesy of Hans W. Paerl,
Bar-built estuaries are formed when sandbars build up along the coastline. These sand bars partially cut off the waters behind them from the sea. Bar-built estuaries are usually shallow, with reduced tidal action. Wind is frequently the most important mixing tool for the fresh and salt water. This type of estuary is common along the Texas and Florida Gulf coasts (East Matagorda Bay), in The Netherlands, and in parts of North Carolina (Albemarle Sound and Pamlico Sound).