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ELMOD

Simulation and analysis of the hydrological and morphological development of the Tidal Elbe for the period from 2013 to 2018

Background and objectives

The overall objective of the ELMOD project is to further deepen our understanding of sediment transport processes in estuaries and coastal seas and to improve the predictive capabilities of three-dimensional hydro- and morphodynamic models.

This objective is being pursued on the basis of studies on the hydrological and morphological development of the tidal Elbe between 2013 and 2018. During this period, various notable hydrological and morphological changes were observed, such as an unusually high increase in tidal range and turbidity, as well as increased deposition in sedimentation hot spots. This was accompanied by, among other things, increased maintenance dredging volumes of fine-grained sediments in the Port of Hamburg, but also in other sections of the fairway, as well as in the adjacent areas and ports. According to current knowledge, the changes described in the system are caused by morphological changes – particularly in the estuary funnel – which are superimposed by the consequences of the phase of below-average upstream inflows that has persisted since summer 2013 and are exacerbated by sediment management that is insufficiently adapted to this development.

Within the scope of ELMOD, the changes in suspended sediment dynamics and morphodynamics observed in the Tideelbe system between 2013 and 2018 are to be investigated using hindcast studies, and the triggering processes identified and analyzed. To this end, the available analyses will be supplemented by measurements in the field and laboratory investigations, the expansion of existing model approaches, and comprehensive modeling work.

Work program

The ELMOD project is divided into three subprojects, which pursue the above-mentioned objectives in cooperation and close exchange with the associated project partners. The networking of the subprojects and the main interfaces are shown in Figure 1.

The federal agency for hydraulic engineering (BAW) is working on subproject 1, “Model application and parameter determination.” In this subproject, various long periods are simulated and analyzed. Integral control variables for comparison with observed changes are known morphological developments, but also a comparison of the maintenance dredging volumes calculated by the model with the known volumes from these years. The university of the Bundeswehr Munich (UniBw) is working on subproject 2, “Model Formation and Parameterization.” Here, model approaches for turbulence, settling velocity, deposition, consolidation, erosion, and bedload transport are adapted, taking into account topographical information below the grid resolution (subgrid). The TUHH is carrying out subproject 3, “Measurements in nature and experimental investigations in the laboratory.” The focus is on measurements of the suspended sediment concentrations near the bed and the consolidation processes in a tidal cycle at different sedimentation hot spots in nature and their replication in the laboratory for the purpose of systematic investigations.