The water authority Noorderzijlvest can start increasing the water storage in De Onlanden in September 2025. On August 14, the project decision for the realization of extra water storage in De Onlanden was established by the Provincial Executive of Drenthe. With the extra water storage, the storage capacity of De Onlanden will increase from 7.5 to 12.7 million cubic meters within the existing dikes. This expansion makes it possible to temporarily store more water during extreme weather conditions before it is discharged into the sea. The extra water storage is expected to be partially operational by the end of 2025/beginning of 2026 and fully completed in 2027. For the implementation of the work, the so-called Hooiweg variant has been chosen. With the project decision, phase one of this variant, the increase of the water storage, can be executed. Two new weirs will be built at Hooiweg for this purpose. When the extra water storage is used, these weirs will rise to retain water. The water authority will also adapt the Doolhof weir in the Peizerdiep and raise the dikes in the water storage area. Additionally, the water authority will increase the pumping capacity of pumping station Zanddijk, raise the access roads of TenneT and Gasunie, and implement protective measures for homes along Roderwolderweg and Moleneind. The capacity of pumping station Sandebuur will also be adjusted. This pumping station is outside the project area but does drain into De Onlanden. Therefore, adjustments will be included in advance. The extra water storage provides space for an additional 5.2 million cubic meters of water. During extreme rainfall, the water level can rise to a maximum of +18 cm NAP (previously -0.20 NAP). This allows for temporarily (for several days) more water to be captured before it is discharged into the sea. In the expansion, as much consideration as possible will be given to the nature in De Onlanden. Refuge hills for animals will be created during high water, the water authority will fill in ditches to retain groundwater longer, topsoil will be removed along ditches, a trench will be created, and the water level will be raised in parts of the area. These measures, developed in collaboration with nature organizations and land managers, strengthen the marsh nature and make the ecosystem more robust. The area between Hooiweg and Leekstermeer will remain outside the extra water storage because it is an important breeding and living area for birds. Some of the nature measures will be implemented in phase one, simultaneously with the expansion of the water storage. The remaining measures will follow in phase two of the project. The draft project decision for the extra water storage was available for inspection from December 19, 2024, to January 30, 2025. A total of eighty objections were received. These objections were carefully weighed by the province when establishing the project decision. Based on the objections and discussions with residents, additional measures and customized solutions were included in the final design. The project decision will take effect 4 weeks after publication. An appeal against the project decision can be made within 6 weeks (from August 21 to October 1, 2025) at the Administrative Jurisdiction Division of the Council of State.