In the north-west of Germany, a series of closure works have been implemented. Initially, the primary aims of these closures were land reclamation and protection against flooding. Subsequently, the focus shifted towards safety and ecological conservation. Closures took place in Meldorf (1978), Nordstrander Bucht (Husum, 1987), and Leyhörn (Greetsiel, 1991).
Around 1975, evolving global perspectives on ecological significance led to a change in the approach to closures. As a result, in northern Germany, several closures were executed differently from their original designs. For instance, while there were plans to completely dam the Leybucht near Greetsiel, only a minor portion was ultimately closed—just enough to meet safety and water management requirements. This made the closure of the remaining area no longer a technical challenge. A discharge sluice and navigation lock were constructed, providing adequate capacity to mitigate currents in the closure gap of the dam.