Bockelmann, Ayla

Büscher, Annette

Rudolph, Elisabeth

Seiffert, Rita

English

Hydraulic Engineering Repository

Conference Paper, Published VersionRudolph, Elisabeth; Bockelmann, Ayla; Büscher, Annette; Seiffert, RitaStorm Surges in German North Sea Estuaries and ClimateChange – Investigating Impacts and Developing AdaptationStrategiesZur Verfügung gestellt in Kooperation mit/Provided in Cooperation with:Kuratorium für Forschung im Küsteningenieurwesen (KFKI)Verfügbar unter/Available at: https://hdl.handle.net/20.500.11970/99535Vorgeschlagene Zitierweise/Suggested citation:Rudolph, Elisabeth; Bockelmann, Ayla; Büscher, Annette; Seiffert, Rita (2014): Storm Surgesin German North Sea Estuaries and Climate Change – Investigating Impacts and DevelopingAdaptation Strategies. In: Lehfeldt, Rainer; Kopmann, Rebekka (Hg.): ICHE 2014.Proceedings of the 11th International Conference on Hydroscience & Engineering. Karlsruhe:Bundesanstalt für Wasserbau. S. 1053-1058.Standardnutzungsbedingungen/Terms of Use:Die Dokumente in HENRY stehen unter der Creative Commons Lizenz CC BY 4.0, sofern keine abweichendenNutzungsbedingungen getroffen wurden. Damit ist sowohl die kommerzielle Nutzung als auch das Teilen, dieWeiterbearbeitung und Speicherung erlaubt. Das Verwenden und das Bearbeiten stehen unter der Bedingung derNamensnennung. Im Einzelfall kann eine restriktivere Lizenz gelten; dann gelten abweichend von den obigenNutzungsbedingungen die in der dort genannten Lizenz gewährten Nutzungsrechte.Documents in HENRY are made available under the Creative Commons License CC BY 4.0, if no other license isapplicable. Under CC BY 4.0 commercial use and sharing, remixing, transforming, and building upon the materialof the work is permitted. In some cases a different, more restrictive license may apply; if applicable the terms ofthe restrictive license will be binding. 1 INTRODUCTION The German Ministry of Transport (BMVI) is interested in the effect of climate change on the waterways in e.g. the German North Sea estuaries and therefore initiated the project KLIWAS (www.kliwas.de). In order to find a strategy for adaptation to climate change it is important to understand today’s situation and analyse the future situation under the influence of climate change. The impact of climate change for the estuaries is investigated, vulnerabilities can be identified and an adaptation strategy can be prepared. This concept will be presented by looking into storm surges in the estuaries along the German Bight. Climate change is expected to cause a global sea-level rise as well as a local sea-level rise in the North Sea, an increase in winter precipitation over Europe that can induce higher river run off in the storm surge season, and an increase in wind speed. These possible consequences of climate change can influence the height of storm surges in the estuaries along the German Bight. A sensitivity study is used to identify areas along the estuaries of Elbe, Jade-Weser and Ems, which are vulnerable in case of storm surges and climate change. In a second step the efficacy of several adapta-tion measures is investigated. Advantages and disadvantages of the adaptation measures can be identified. The results give the chance to develop an adaptation route for the waterways in the estuaries of Elbe, Jade-Weser and Ems in order to mitigate the problems caused by climate change.  2 SENSITIVITY STUDY: IMPACTS OF CLIMATE CHANGE The height of a storm surge in an estuary is determined by the water level at the estuaries boundary to the North Sea, the river run off into the estuary and the wind field over the estuary. A sensitivity study on storm surges in times of climate change is used to investigate scenarios that are not intended to represent a full description of the future but highlight central elements of a possible future. Storm Surges in German North Sea Estuaries and Climate Change – Investigating Impacts and Developing Adaptation Strategies E. Rudolph, A. Bockelmann, A. Büscher & R. Seiffert Federal Waterways and Research Institute, Hamburg, Germany  ABSTRACT: As climate will change in this century and beyond, the German Ministry of Transport (BMVI) is interested in the effect of climate change on the waterways in the German North Sea estuaries and therefore initiated the project KLIWAS (www.kliwas.de). In order to find a strategy for adaptation to climate change it is important to understand today’s situation and analyse the future situation under the influence of climate change. This concept will be presented by looking into storm surges in the German Bight. A sensitivity study is used to identify areas along the estuaries of Elbe, Jade-Weser and Ems, which are vulnerable in case of storm surges and climate change. In a second step the efficacy of several adaptation measures is investigated. Advantages and disadvantages of the adaptation measures can be identified. The results give the chance to develop an adaptation route for the waterways in the estuaries of Elbe, Jade-Weser and Ems in order to mitigate the problems caused by climate change.  Keywords: Storm surge scenario, Climate change, Sensitivity study, Hydrodynamic numerical model, Wind, Sea-level rise, River run off ICHE 2014, Hamburg - Lehfeldt & Kopmann (eds) - © 2014 Bundesanstalt für Wasserbau ISBN 978-3-939230-32-81053As a result of this sensitivity study, in each estuary areas can be found where the water levels are influ-enced due to a change in the parameters sea-level rise, river run off or local wind. The local impact of global climate change on the water levels along an estuary can be identified (Schulte-Rentrop and Ru-dolph, 2012, Rudolph, 2014). It shows that today’s challenges are likely to grow as a result of climate change (Seiffert and Hesser, 2014).   Figure 3. Sensitivity study sea-level rise in combination with increase of river run off: Highest water level during storm surge HW along the estuaries of Elbe (top), Weser (middle) and Ems (bottom) for a sea-level rise at the mouth of the estu-aries of 25 cm, 80 cm and 115 cm. Black indicates a river run off for the Elbe of 500 m3/s, Weser of 250 m3/s and Ems of 32 m3/s, grey indicates a river run off for Elbe and Weser of 3000 m3/s and Ems of 700 m3/s. 3 ADAPTATION MEASURES In a second step the efficacy of several adaptation measures is investigated. As an alternative to increas-ing the dike height along the whole estuary, narrow the mouth of the estuary and storm surge barriers in the mouth of the estuary are investigated. Again a sensitivity study varying the parameters that might change in a future climate, such as sea-level rise or increase of river run off, is used to test the efficacy of the adaptation measures. 3.1 Narrow the mouth of the estuary In order to narrow the mouth of the estuary several measures such as increasing an existing sandbank, building a new sandbank or building a dam (Seiffert and Hesser, 2014) are investigated. Figure 4 illus-trates e.g. the position of a dam of NHN + 10 m height that is built in the area of Neufelder Sand as a nar-rowing measure for the Elbe estuary.  1055The barrier can only protect against storm surges of a certain height. It is possible to identify a sea-level rise scenario where the barrier will not give full protection anymore. It can be considered to operate the barrier differently or to adapt the barrier to different design water levels. 4 RESULTS In order to develop a strategy for adaptation to climate change for the waterways in the German estuaries it is important to understand today’s situation and to analyse the impacts of climate change. The impact of climate change on storm surges in the estuaries of Elbe, Weser and Ems is investigated using a sensitivity study. This study analyses the influence of sea-level rise at the mouth of the estuary, wind over the estu-ary and river run off.  The efficacy of the adaptation measures “narrow the mouth of the estuary” and “storm surge barrier” is investigated using again a sensitivity study. It shows, that to narrow the mouth of an estuary can reduce but not compensate the effect of a sea-level rise on the highest water levels during storm surge whereas a storm surge barrier protects an estuary against storm surges even in combination with sea-level rise. But both adaptation measures cause restrictions for the ships using the waterways in the estuaries. The results of the sensitivity studies help to identify vulnerabilities of e. g. shore protection in each es-tuary due to climate change. Several adaptation measures are tested in a second sensitivity study. The ad-vantages and disadvantages can be investigated. The results give a chance to develop an adaptation route (Lowe et al., 2009) for the waterways in the estuaries of Elbe, Jade-Weser and Ems in order to mitigate problems caused by climate change. REFERENCES BAW (2004). Validation document - Mathematical Model UnTRIM. Bericht der Bundesanstalt für Wasserbau - Dienststelle Hamburg. (see BAWiki: www.baw.de) Casulli, V., Walters. R. A. (2000). An unstructured three dimensional model based on the shallow water equations. Interna-tional Journal for Numerical Methods in Fluids, 32: pp. 331-348. KLIWAS (2011). Conference Proceedings KLIWAS - Impacts of Climate Change on Waterways and Navigation in Germany, Second Status Conference – Federal Ministry of Transport, Building and Urban Development, Berlin – 25 and 26 October 2011. ISBN 978-3-940247-05-6. Lowe, J. A., Howard, T., Pardaens, A., Tinker, J., Jenkins, G., Ridley, J., Holt, J., Wakelin, S., Wolf, J., Horsburgh, K., Reeder, T., Milne, G., Bradley, S., Dye, S. (2009): UK Climate Projections Science Report: Marine and Coastal Projections: Met Office Hadley Centre. Exeter, UK. ISBN 978-1-906360-03-0. Rudolph, E. (2014). Storm Surges in the Estuaries of Elbe, Jade-Weser and Ems. Die Küste, Vol. 81. Schulte-Rentrop, A., Rudolph, E. (2012). A Sensitivity Study of Storm Surges Under the Conditions of Climate Change in the Elbe Estuary. In: FILHO, W. L. (ed.): Climate Change and Disaster Risk Management. Berlin, 295-309, doi: 10.1007/978-3-642-31110-9_18. Seiffert, R., Hesser, F. (2014) Investigating climate change impacts and adaptation strategies in German estuaries. Die Küste, Vol. 81. 1057

Storm Surges in German North Sea Estuaries and Climate Change – Investigating Impacts and Developing Adaptation Strategies

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Storm Surges in German North Sea Estuaries and Climate Change – Investigating Impacts and Developing Adaptation Strategies

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