Dutch province opposes German plans to deepen the Ems River

The Dutch Province of Groningen opposes German Chancellor Friedrich Merz’s plan to deepen the shipping channel of the Ems River by one metre, Dutch regional broadcaster RTV Noord reported on 19 May. Concerns about these plans have existed for several years due to the risk of further deterioration of water quality in the Ems-Dollard estuary.

According to RTV Noord, during a recent visit to the Moormerland region, just across the border in Germany, Merz reiterated his long-standing desire to deepen the shipping channel. Industries located along the Ems, such as Volkswagen and shipyards including Meyer Werft, would then be accessible to larger vessels. About 90 percent of global trade takes place via waterways, the Chancellor emphasised, adding that northern Germany therefore has a ‘major interest in ensuring these routes are well developed’.

Deterioration of water quality

In Groningen, where the river flows into the Ems-Dollard estuary, these plans have for years raised concerns about the further deterioration of water and ecological quality. The Ems-Dollard is one of only two remaining estuaries in the Netherlands. The mixing of fresh and salt water creates unique environmental conditions and makes the estuary an important habitat for species such as seals, spotted redshanks, pied avocets, and common scoters.

Excess sediment

Partly due to constant dredging activities, water and ecological quality in the estuary have significantly declined. For years, the area has suffered from an excess of sediment and permanently suspended silt. Recent measurements show sediment concentrations of up to 160 milligrams per litre in the Dollard. For a healthy ecosystem, these concentrations in the central part of the estuary need to be reduced by 20 to 50 percent.

This turbidity reduces the penetration of sunlight into the water, limiting the growth of algae and aquatic plants. It also reduces visibility for predatory fish, making hunting more difficult. These and other mechanisms have likely contributed to the decline in biomass and biodiversity in the area. The once-lush seagrass meadows on the Hond-Paap tidal flat have been decimated, according to a recent monitoring report. Plant density is limited (coverage below 5 percent), and in 2024 the total surface area was halved to 6.88 hectares compared with the previous year.

Shellfish beds are no longer found in the Dollard due to the large amounts of sediment. Furthermore, ‘a notable observation in 2024 was the absence of a large-scale mussel spatfall in the Ems-Dollard’, according to the report. During a spatfall, mussel larvae that have been drifting in seawater after fertilisation settle on tidal flats, existing mussel beds, or other structures.

Surprising remarks

Because of the already poor condition of water quality in the Ems-Dollard, the Province of Groningen stated in 2024 that it opposed the deepening plans. Dutch and German environmental organisations also expressed concerns at that time. According to the Wadden Association, further deepening of the Ems would be the final blow to the necessary ecological restoration of the Ems-Dollard.

Speaking to RTV Noord, regional executive Leo Wenneger described Merz’s renewed remarks as ‘surprising’. “We had not been informed about this,” Wenneger said. He also stressed that both the Ems-Dollard and the Wadden Sea are protected Natura 2000 areas, and that the Wadden Sea is additionally a UNESCO World Heritage Site, for which the Netherlands, Germany, and Denmark share responsibility. Wenneger intends to once again inform the German government that the Province of Groningen opposes deepening the Ems.

Ems-Dollard 2050

Through the Ems-Dollard 2050 programme, public authorities, companies, and environmental organisations are working together to restore water and ecological quality in the area. Participants include the Province of Groningen, Rijkswaterstaat, and the regional water authorities Hunze en Aa’s and Noorderzijlvest. Measures include experiments with sediment capture outside the dikes, using sheltered areas between brushwood dams to trap silt. The partners also aim to remove at least one million tonnes of sediment annually and use it for dike reinforcement and raising low-lying agricultural land. Whether these efforts will achieve the required 20 to 50 percent reduction in turbidity in the central estuary remains uncertain. Ongoing monitoring during programme implementation is expected to provide answers, although restoration is anticipated to require a long-term commitment.

New insights necessary

Recently, criticism of the programme’s priorities was voiced by Katja Philippart, Professor of Marine Ecology at Utrecht University, researcher at the Royal Netherlands Institute for Sea Research, and director of the Wadden Academy. “The programme is putting all its efforts into reducing turbidity, but that assumption is ten years old. New insights suggest that it may no longer be light availability but rather nutrient availability, particularly phosphate, that limits the growth of suspended algae. In that case, by 2050 we may have clear water, but no suspended algae left.”

This article was published first by the Dutch platform for water professionals H2O Magazine