Improved water quality and ecological restoration

It is better for nature if there is a more natural transition zone between fresh and salt water in Lauwersmeer and the Wadden Sea. This creates more variety in environments (salt, brackish, and fresh), which increases the biodiversity of fish, underwater animals, birds, and plants. Greater biodiversity also improves water quality. 
 

The Lauwersmeer area used to be a reed bed, ideal for reed birds such as bearded reedlings and reed warblers. Trees could not grow on the salty soil. Now that Lauwersmeer is fresh, trees do grow there. One nature conservation goal is to allow both trees and reeds to grow. Grazing by cows and horses can prevent afforestation. In the northern part, a brackish environment will also create more space for reeds. Elsewhere in the area, we want to preserve trees for breeding birds, such as white-tailed eagles.
 

A 70-hectare tidal area is being created at the Marnewaard military training area. A passage will be created in the sea dike to allow water from the Wadden Sea to flow into the tidal area. This passage will be closed at high tide. The transition between fresh and salt water is gradual here. This helps the Wadden Sea ecosystem. There is currently no connection between this tidal area and Lauwersmeer, and therefore no effect on Lauwersmeer. In the long term, this presents an opportunity for nature to establish a connection, thereby improving fish passability between the Wadden Sea, Marnewaard, and the hinterland.

The fish migration river is an opening in the Afsluitdijk. This allows migratory fish to swim between the salty Wadden Sea and the fresh IJsselmeer at all times. This is a major technical solution for fish migration. At Lauwersmeer, we want more than just fish migration. A more natural transition between fresh and salt water creates different environments (salt, brackish, and fresh). This increases the biodiversity of fish, other underwater animals, birds, and plants. And that improves water quality.

Fish-friendly discharge is a method whereby water managers control discharge pipes and locks in such a way that fish can move (migrate) safely between different bodies of water. This is particularly important for migratory fish that need to swim from salt to fresh water to spawn or grow. The flow velocity and timing of discharge are taken into account, which helps to support fish populations and improve the ecological balance.

The Noorderzijlvest Water Authority has adjusted the discharge management at the R.J. Cleveringsluizen locks. From March to May, discharging mainly takes place after sunrise. The gates are opened at a constant level, which means that the locks remain open longer and fish have more time to migrate.