Improved water quality and ecological restoration

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

The lake 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 lake Lauwersmeer is freshwater, trees do grow there. One nature conservation goal is to allow both trees and reeds to grow. Grazing by cows and horses can prevent forestation. 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 exercise area. A passage will be created in the sea dyke to allow water from the Wadden Sea to flow into the tidal area. This passage will be closed at high tide. The transition between freshwater and saltwater is gradual here. This helps the ecosystem of the Wadden Sea. There is currently no connection between this tidal area and lake Lauwersmeer, and therefore there is no effect on lake Lauwersmeer. In the long term, this presents an opportunity for nature to establish a connection, thereby improving the passage of fish 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 freshwater lake IJsselmeer at all times. This is a major technical solution for fish migration. At lake Lauwersmeer, we want more than just fish migration. A more natural transition between freshwater and saltwater creates different environments (salt, brackish, and fresh). This increases the biodiversity of fish, other aquatic animals, birds, and plants. And that improves water quality.

Fish-friendly discharge is a method used by water managers to control discharge sluices and locks in such a way that fish can move (migrate) safely between different bodies of water. This is particularly important to migratory fish that need to swim from saltwater to freshwater 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. Clevering locks. From March to May, discharge mainly takes place after sunrise. The gates are opened at a constant level, allowing the locks to remain open longer and giving fish more time to migrate.