Have you ever seen a lagoon?
Bays that become separated from the sea as a result of the post-glacial land uplift are known as flads, gloes, and gloe lakes. A higher threshold formed by a moraine ridge, a sandbank or bedrock at the mouth of the bay separates the bay from the sea as the land rises. Enclosing inlets are known as flads whilst they are still connected to the sea. A flad develops into a gloe when seawater enters it only occasionally during periods of high water and storms. A gloe lake, however, has become completely separated from the sea and gradually turns into freshwater.
On the sheltered, shallow shores of Vattaja, sand accumulated by the waves speeds up the formation of flads and gloes. A single stormy year may be enough for accumulated sand to cut a bay off from the sea. Within just a few years, waves can build a sand barrier high enough to prevent seawater from entering altogether, turning the bay into a gloe lake.
Flads and gloes are also known as lagoons. As the land continues to rise along this low-lying coast, new lagoons are constantly being formed.
From the birdwatching tower, you can see the sand barrier that separates a gloe lake from the sea.