The port of Hamburg, located at the Elbe estuary in Northern Germany, is challenged by a high maintenance effort due to sediment which is transported by a powerful flood current from the North Sea into the upper estuary and port area. This leads to high costs for the port, but also to unfavorable environmental conditions for protected nature areas in the estuary.
The shape of the estuary has been modified continuously over the past centuries due to land reclamation, deepening of the shipping channel and cut-off of tributaries for flood protection – resulting in the current effects of sedimentation for economy and ecology. As an answer to these unfavorable conditions an adapted sediment management strategy supported by river engineering measures to create space for the estuary are considered to be suited to contribute to the reduction of tidal energy and the upstream sediment transport. In 2012 Hamburg Port Authority (HPA) started the construction works for the pilot project “Kreetsand/Spadenlander Busch”. This river engineering measure has three objectives. (1) It will contribute to reducing the tidal energy by creating approximately 1.1 mill. m3 of additional tidal volume. (2) Valuable natural habitats like shallow water area, mudflats, reed and floodplain forests will be created. (3) Parts of the area will function as recreational area for residents where they will get the opportunity to experience a tidal influenced landscape.
Local residents and stakeholders, including environmental organizations and local administration, were involved right from the beginning in the planning process in 2008. During the construction process the complexity of the tidal dynamics and estuarine functioning as well as the construction of the area itself are explained by informative posters in a publically accessible information shed located at the site on the dyke.
After the works will be finished in 2020, natural processes are allowed to form the embankments inside the area by erosion and sedimentation and thus create naturally changing habitats.
However, the effect of the pilot “Kreetsand/Spadenlander Busch” on decreasing tidal energy is only marginal due to its size and its location within the estuary. More river engineering measures consisting of larger areas have to be planned and carried out. But finding a suited location for further measures within the 140 kilometers long estuarine stretch seems to be rather complicated due to the individual interests of different federal states and various stakeholder groups. Therefore an estuary partnership, the so-called ´Forum Tideelbe´, was found in 2016. All affected stakeholders of the estuary are involved, e.g. representatives of the administrations of the three responsible federal states, HPA and the German Federal Waterways and Shipping Administration (WSV), municipalities, environmental organizations, trade and industry representatives, fishermen, farmers, water boards, leisure organizations, etc. It is their task to choose and propose suited locations to the responsible administrations for conducting further measures, e.g. reconnecting anabranches to the main estuary channel or setting back dykes to create more space for the estuary. Main criteria are the contribution of the measure to (1) reduce tidal energy and related upstream sediment transport, (2) create ecological valuable habitats, and (3) feasibility. Furthermore the whole process should lead to a better understanding of natural estuarine processes and improve the communication and cooperation between different stakeholder groups and administrations. Based on the recommendations responsible administrative bodies will make their decision. So far, this kind of process, i.e. involving various societal groups in estuarine management, is rather unique in Germany.
The presentation will give an overview on the development of the process, lessons learned and on the current state.
Conference attendees will benefit from the experiences made and lessons learned on how economic, ecological and societal interests will be combined in river engineering measures being a part of integrated management of estuaries - one of the most dynamic and complex natural environments.