Langwarder Groden

Salt marshes improvement by removing summerdike

The Langwarder Groden is part of the Wadden Sea National Park. The removing of the summer dike created extensive mud flats, shallow ater areas and salt marshes, habitats for many breeding and resting birds.

Langwarder Groden

coordinates Google Maps 53.6072692 , 8.3268197

The summer dike was build in the 30th-40th. They builded the summer dike rather massive and so high that the inner dike grounds have never seen salt water. The landusers where very satisfied because they had really good green land.

Anna Appel and Marta Jacuniak-Suda ©Michiel Firet

The Langwarder Groden is a compensation project for the Jaden Wisardport. Anna Appel, National Parkverwaltung Niedersächsisches Wattenmeer, tells us more about the project.

It is an example of ‘managed reallignment’. There was a struggle with local citizens to remove the summerdike because they were afraid of their safety and of loss of the cultural landscape (a long history of changing the dike-line; artifacts from year 1100). A study into what happens if the summer dike is completely removed had a surprising result. The project would not be very happy about this because the main parts of the Langwarder Groden are so high that they would not flood regularly enough for a real salt marsh development. The next step was to find a solution for this. How can the compensation measures be implemented? So they removed soil to lower the service and raise the main embankment. A win-win situation. Traditional grazing is part of the solution to develop a traditional salt marsh.


In 2014, the salt water was let in and nature did most of the development it itself. And it still works. In 2014 it was just black with no creeks at all. It had cut a bit to instruct the water. Research into the force of the water indicated that it will not damage the main dike even in a storm. There is some damage to the summer dike. But that is part of natural development. Maybe in the future it will be necessary to change the paths. An impressive vegetation development can be seen in the salt marshes.

The prediction was that sedimentation would occur and that is being measured. There is sedimentation in all places, including the high sides that only flood with storms. The development of the trench is slowing down. From the whitening at first it went very wide (the bridge had to be secured) then it gets narrower and now it is bended.

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