Nissum Fjord

Nissum Fjord is an inlet located in West Jutland, west of Vemb and is demarcated from the North Sea by a 1.3 km wide isthmus, Bøvling Klit, and passes through a lock in Thorsminde. The inlet has a water area of 70 km2 or 7,000 ha. but the average water depth is only about 1 meter, and the deepest areas in Felsted Kog and the center of the inlet are between 2 and 3 meters. The northern part of the inlet, called Bøvling Fjord, is so shallow that it is sometimes completely drained by strong winds.

Source: Wikipedia