Gerald Herrling, Heiko Knaack, Ralf Kaiser, Hanz Dieter Niemeyer


In the Ems-Dollard estuary at the southern North Sea coast a revaluation of design water levels along the German dykes has become necessary, since the safety margin for sea level rise was increased by 25 cm due to a decision of the Lower Saxon Ministry for Environment and Climate Protection. The upstream part of the estuary is protected against high storm surges by a storm surge barrier. The closure of the barrier effects downstream surge water levels due to partial reflection. Deterministic-mathematical modeling is applied to evaluate design water levels and design wave run-up. Three severe storm surge events have been hindcasted by a cascade of three hierarchical models from the Continental Shelf over the German Bight into the area of interest. The models are forced by non-stationary and spatially varying data of atmospheric pressure, wind velocities and directions available of meteorological model investigations. The verification of the storm surge model with water level observations yields good agreements. With respect to legal boundary conditions, the single-value-method is applied to determine the highest expected high water level at Emden. Starting from this target water level, the wind velocities in the meteorological boundary conditions are increased with the aim to increase the surge level at the coast and to match the predetermined design water level at Emden. The responding water levels in the Ems-Dollard estuary assign the new design water levels.


storm surge modeling; design water level; Ems-Dollard estuary; North Sea, single-value-method; storm surge barrier; Delft3D


Booij, N., R.C. Ris, L.H. Holthuijsen. 1999. A Third-Generation Wave Model for Coastal Regions. Part I, Model Description and Validation, J. Geophys. Research, 104, C4.http://dx.doi.org/10.1029/98JC02622

Bruss, G., R. Mayerle. 2009. Investigations on the influence of the wind drag coefficient in storm surge models, Proceedings of the 3rd International Conference in Ocean Engineering, Madras, 325-332.

Deltares. 2009. User Manual Delft3D-FLOW. Simulation of multi-dimensional hydrodynamic and transport phenomena, including sediments. Deltares, Delft, The Netherlands. 644 pp.

Elsebach, J., R. Kaiser, H.D. Niemeyer. 2009. Ermittlung von Bemessungsseegang und –wellenauflauf für die Deiche am Ems-Dollart Ästuar mit mathematischen Modellierungen. internal report 03/2010. NLWKN-Coastal Research Station (unpublished).

Herrling, G., H. Knaack, R. Kaiser, H.D. Niemeyer. 2010. Ermittlung der Bemessungswasserstände im Ems-Dollart Ästuar mit mathematischen Modellierungen. internal report 02/2010. NLWKNCoastal Research Station (unpublished).

Lüders, K., G. Leis. 1963. Niedersächsisches Deichgesetz - Kommentar. Verl. Wasser u. Boden, Hamburg.

Mayerle, R., C. Winter. 2002. Determination of open sea boundary conditions for small scale coastal models. Validation of the CSM-GBM-Nesting. FTZ Büsum- Coastal Research Laboratory/Univers. of Kiel (unpublished).

Niemeyer, H.D. 1997. Überprüfung der Bestickhöhen von Deichstrecken an der Unterems, internal report 05/1997, NLÖ- Coastal Research Station (unpublished).

Niemeyer, H.D., R. Kaiser. 2001. Evaluation of Design Water Levels and Design Wave Run-up for an Estuarine Costal Protection Master Plan. Proc. 27th Int. Conf. Coast. Engg., Sydney/Australia, ASCE, New York.

Smith, S.D., E.G. Banke. 1975. Variation of the sea surface drag coefficient with wind speed. Quart. J. Roy. Meteorol. Soc. 101, 665-673.

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