Hamburg Port Authority, Kreetsand Former Dredged Material Field Restored as Tidal Habitat
The tidal Elbe has lost about 90 percent of its formerly flooded area over the centuries (Hamburg Port Authority, n.d.). The port authority links this loss to more sedimentation in the Hamburg area and more dredging (Hamburg Port Authority, n.d.). The Kreetsand site was a former dredged material field. It had already been set back behind the dike, but it lay so high that it was very rarely flooded (Hamburg Port Authority, n.d.). The Hamburg Port Authority (HPA) turned this disused port land into a near natural shallow water area open to the tide. This is port-authority-led habitat creation linked to sediment management, not the dismantling of port infrastructure.
Approach
Reuse of disused port land. HPA chose a former dredged material field inside the port area and lowered it so that the tide could reach it again (Hamburg Port Authority, n.d.).
Large earthworks, moved by water. About two million cubic meters of soil had to be removed. Much of it was moved by waterway rather than by road (Hamburg Port Authority, n.d.).
Separate handling of contaminated soil. Contaminated soils were taken to landfills for safe disposal. Most of the other material was set aside for use in other projects (Hamburg Port Authority, n.d.).
Habitat design. The new area is a refuge and breeding site for fish and a potential nesting site for the white-tailed eagle. It also serves waterbirds, amphibians and floodplain forest, and is expected to suit the hemlock water dropwort, a plant found only on the Elbe (Hamburg Port Authority, n.d.).
Monitoring and learning. HPA treats Kreetsand as a pilot project. It will monitor the area ecologically and hydrologically over the long term together with the responsible city environment authority (BUKEA), to derive guidelines for future projects. A small information hut on the dike informed the public during construction (Hamburg Port Authority, n.d.).
Results
HPA reports that the project added 30 hectares of new water area subject to ebb and flood tides. HPA announced completion of the pilot project in June 2023, after construction from 2012 to 2022 (Hamburg Port Authority, 2023). Construction took about ten years and cost almost 80 million euros. The project qualified as an excellence project of the International Building Exhibition (IBA) Hamburg in 2009, and in 2014 PIANC awarded it first prize as Best Practice in Working with Nature. HPA states that the extra flood space is intended to improve tidal currents and relieve the sediment budget (Hamburg Port Authority, n.d.).
Transferability
DMC ports often hold old spoil disposal fields, reclaimed plots or other port land that no longer serves operations. Kreetsand shows that such land can be converted into habitat rather than left idle. Useful elements are separating contaminated soil for safe disposal from clean soil that can be reused, moving bulk material by water where possible, designing the site for both ecological and operational benefits (such as sediment management), and committing to long term monitoring with the environmental regulator. The high cost and long timeline show that such projects need early planning and budgeting.
Sources
All information used for this case study was based on publicly available resources.
- Hamburg Port Authority. n.d. Flachwassergebiet Kreetsand fertiggestellt: 30 Hektar mehr Tideelbe. Tideelbe.info (published by Hamburg Port Authority AöR). (opens in new tab)
- Hamburg Port Authority. 2023. HPA schließt Pilotprojekt "Flachwassergebiet Kreetsand" erfolgreich ab. Press release, 2 June 2023. (opens in new tab)