Concerns rise over hypoxia in Danish waters as Vejle Municipality addresses oxygen depletion issues

In Danish waters, concerns about oxygen depletion are back in focus as a new report detailing hypoxia is set to be released. Preliminary measurements have already indicated areas suffering from moderate to severe oxygen deficiency this year, notably in Vejle Yderfjord.

Vejle Municipality has proactively begun efforts to address hypoxia even before the full report’s release. Since 2022, in collaboration with the Southern Denmark University (SDU), the municipality has been investigating nitrogen runoff from the Vejle Å river basin into the fjord, as nitrogen is the primary contributor to oxygen depletion in Danish waters. Recent studies have identified two key waterways, Fyle Bæk and Ødsted Bæk, as significant sources of this nitrogen.

Hanne Fogh Vinther, a biologist with Vejle Municipality, explained their methodical approach to pinpoint nutrient sources: “Instead of attributing the entire problem to Fyle Bæk and Østded Bæk, we aim to specify where the nutrients are coming from.” She noted that while other areas also contribute to nitrogen runoff, discharges from fish farms and sewage treatment plants have a lesser impact.

The findings will guide targeted actions for improving water quality, such as encouraging farmers to alter agricultural practices or establish wetlands to filter nitrogen before it enters the waterways. The Danish government recently allocated 39 million kroner to Vejle Municipality to enhance the condition of Vejle Fjord, part of a broader initiative to address water environmental issues.

Despite not having all analyses finalized, Vejle Municipality is already engaging with landowners to explore potential solutions. Farmer Keld Hjort, who has fields where rainwater containing nitrogen flows into Fyle Bæk, welcomes the initiative and hopes it will lead to effective measures without having to take farmland out of production.