Environment – Protecting dunes on North Sea islands for winter – Wikipedia

Norderney/Languj (dpa/Lenny) – After the sometimes severe loss of sand in the East Frisian Islands as a result of about 20 storms last winter, the protective sand dunes are now being prepared for the upcoming season. The main focus is on the islands of Norderney, Langoge and Wangeroge, as the recently announced Lower Saxony State Agency for Water Management, Coastal Protection and Nature Conservation (NLWKN). As dune reinforcement at Wangerooge nears completion, heavy equipment will be used at Langeoog and Norderney in the next few weeks.

In general, the authority plans to invest about 15 million euros for the work – the money comes from the joint federal and state mission to improve agricultural structures and protect the coasts. In addition, the state government pledged special funds of five million euros. A total of about 600,000 cubic meters of sand will be used in the three projects.

Due to the rising waters and swell during storm surges, erosion has occurred on all islands on the protective sand dunes, Frank Torrens, chief of the responsible NLWKN operation in the north. The construction process now revolves around fully restoring the protective function of the dunes. The ‘Build with Nature’ principle is followed through sand regeneration, dune strengthening and sand trapping procedures.

Like levees, protective sand dunes protect the interior of the islands and thus the settlements from flooding. At Langeoog and Wangerooge, large sand bunkers built in front of protective dunes were where corpses worn out by storms were carried. In Norderney, the protective sand dunes were gnawed so hard in one section by the North Sea that cliff edges formed to a depth of 20 metres.

Torrens emphasized that all construction procedures were carried out in consultation with the island’s communities. However, impacts on tourism cannot be ruled out in the middle of the main season, as there is only a small time window available to operate until the start of the next storm surge season in the fall. Everything should be ready by October. An overview of what NLWKN plans on the three islands:

– Norderney: Two existing dune chains in the particularly affected section of Kugelbake Beach will be strengthened. Among other things, 125,000 cubic meters of sand will be installed with a length of about 900 meters. The protective sand dunes are important to the island as they protect the eastern part of the city as well as the drinking water catchment area from flooding. The sand is sucked up from the seabed west of Norderney by a special ship and then transported to the damaged part of the coast.

The material is then pumped to shore from the ship through a 350-meter rinse tube and transported from there to the dune chain by dump trucks. “Logistically speaking, this is a very big challenge,” Torrens said. Until now, there has been no action of this magnitude in the East Frisian Islands. The costs of the measures amount to approximately 3.7 million euros.

– Langeoog: In front of the protective sand dunes of the so-called Pirolatal in Langeoog, storms swept the sand deposit about 700 meters long. There is now about 450,000 cubic meters of sand about 50 meters wide that is washed there. There is no alternative to this measure, Torrens said – otherwise Langeog, like the other islands, will also need structural coastal protection. To date, the island is the only one that does not have solid wealth. The sand dunes off the Birola Valley protect the island’s important freshwater lens.

Similar to Norderney, the sand is brought from the sea west of Langeoog by a special ship. Then a two-kilometer steel pipeline is used to wash the sand on the beach. The procedure will cost 6.5 million euros. According to expert Torrens, protection should last three to five years if the storm is mild. However, the last influx was in 2020.

– Wangerooge: To the east of Wangerooge’s Bathing Beach, storms hit the sand dunes in front of the so-called northeastern dunes. Much of the 25,000 m3 of planned 600 m long sand has already been deposited. Torrens said that work should be completed soon.

© dpa-infocom, dpa: 220627-99-813039 / 4

Leave a Comment