Case studies: Tidal Flush Basin

Connecting inside and outside located natural water areas

The Tidal Flush Basin coastal lab seeks to create additional opportunities for fish and other species’ migration between outside saltwater conditions and inland freshwater conditions. It connects inside and outside located natural water areas.

Tidal flush basin / image by Henk de Boer


The tidal flush basin influences the sedimentation pattern of a gully, used for navigation, by using, and partly manipulating the tidal movements of water masses. Hence, the gully continues to be accessible for small boats. As compensation for the invasion of Natura2000 Waddensea area, inland nature values are to be established at farm lands. Investigation and negotiation is underway to define where, how and under what conditions the combination can be realised.


Investigations on technical and ecological opportunities have contributed to a knowledge fundament. Land availability seems to have changed favourably, and has to be confirmed in an Open Planning  Process from May 2020 onwards.

Local context

Noordpolderzijl is the Netherlands' most northerly located harbouwithout dyke protection. It serves as a flee-harbour at the eastern part of the Waddensea. All support to develop the Noordpolderzijl area comes from provincial, municipal and water management and Natural resources organisations. However, as always in the Waddensea, many stakeholders anxiously scrutinise all proposed changes in the Waddensea and in the agricultural adjacent areas.

Future research directions

  • The process of realisation


All documents of the BwN project can be found at publications, below you find the documents belonging to this specific case study: