Vistula Lagoon Vistula Lagoon The Vistula Lagoon (; or "Kaliningradskiy Zaliv"; ; ) is a brackish water lagoon on the Baltic Sea roughly 56 miles (90 km) long, 6 to 15 miles (10 to 19 km) wide, and up to 17 feet (5 m) deep, separated from Gdańsk Bay by the Vistula Spit. It is now known as the Vistula Bay or Vistula Gulf. The modern German name, "Frisches Haff", is derived from an earlier form, "Friesisches Haff". The lagoon is a mouth of a few branches of the Vistula River, notably the Nogat, and the Pregolya River. It is connected to
Venetian Lagoon the network of dredged channels are called, while around 80% consists of mud flats, tidal shallows and salt marshes. The lagoon is the largest wetland in the Mediterranean Basin. It is connected to the Adriatic Sea by three inlets: Lido, Malamocco and Chioggia. Sited at the end of a largely enclosed sea, the lagoon is subject to high variations in water level, the most extreme being the spring tides known as the "" (Italian for "high water"), which regularly flood much of Venice. The nearby Marano-Grado Lagoon, with a surface area of around , is the northernmost lagoon in the