Influence of Sea Level Rise on Highest

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Influence of sea level rise on highest water levels during storm surges in the Ems estuary The Project EXTREMENESS The project EXTREMENESS (Extreme North Sea Storm Surges and Their Consequences) investigates the interaction of factors and conditions contributing to the formation of storm surges. A variety of data sets are searched for conditions associated with extreme storm surge events. These events are modified in a way that their intensity is enhanced, e.g. by shifting the tidal phase or by applying a sea level rise. The objectiveREFSF06 is to examine whether thereREFSF06 might be exceptional combinations of conditions that can lead to exceptional high or long lasting water levels which have not been observed yet but which are water level Q0032_SLR000_SPWg Knoten "Emden_(Modell)" st water level Q0032_SLR050_SPWg Knoten "Emden_(Modell)" possible and plausible. As a first example, the historical storm surge of 1 Novemberwater 2006 level Q0032_SLR100_SPWg is analyzed Knoten "Emden_(Modell)". The focus of the analyses are the estuaries of the water level Messung Emden_Neue_Seeschleuse_/_Pegel_/_Ems_/_WSA_Emden_/_WSA_Emden_Pegelkoord_xls rivers Elbe and Ems. 6.5 6. observedWasserstand water levels Messung Emden_Neue_Seeschleuse_/_Pegel_/_Ems_/_WSA_Emden_/_WSA_Emden_Pegelkoord_xls

mMSL SLRWasserstand = 0cm, closed Q0032_SLR000_SPWg storm surge barrier Knoten "Emden_(Modell)"

5.5 SLRWasserstand = 50cm, closed Q0032_SLR050_SPWg storm surge barrier Knoten "Emden_(Modell)" waterlevel SLR = 100cm, closed storm surge barrier 5. Wasserstand Q0032_SLR100_SPWg Knoten "Emden_(Modell)" 4.5 6.5 4. 3.5 6. Fig. 2: Storm surge barrier 3. mNHN near Gandersum in the river 2.5 5.5

Ems (source: BAW) 2. Wasserstand 1.5 5. 1. 0.5 4.5 0 -0.5 4. -1. 10/31/2006 10/31/20063.5 11/01/2006 11/01/2006 11/02/2006 00:00:00 12:00:00 00:00:00 12:00:00 00:00:00 UTC UTC UTC UTC UTC USER: BAW-AK (ReferatK3) FILE: gview2d0014.cgm 3. Fig. 3: Measured and simulated water levels at Emden (Ems) Program GVIEW2D 06.25.2018 2.5 Storm surge of ퟏ퐬퐭 November 2006 On 1st November2. 2006, a severe storm caused high water levels in the German Bight and in the Ems estuary (see figure 3). Due to 1.5 strong north-west winds, water was retained in the Ems estuary causing the low1. water preceding the storm surge to remain relatively high.0.5 Furthermore, the peak of the storm occurred simultaneously with high tide and lead to the highest water levels since 1906 in the0 Ems. During this event the storm surge barrier near Gandersum-0.5 (see figure 2) was closed. This event is modelled using the hydrodynamic-numerical model UnTRIM2 (Casulli-1. , 2008). The model region encompasses the 31.10.2006 31.10.2006 01.11.2006 01.11.2006 02.11.2006 Fig. 1: Topography of the modelled region (German Bight, southeastern corner of North Sea); black line denotes German Bight00:00:00 and the estuaries of the rivers12:00:00 Ems, Weser and Elbe 00:00:00 12:00:00 00:00:00 1 Hochwasserstand HW Q0032_SLR0 KUKA-NSEE profile where highest water levels were evaluated and red dot marks position of storm surge barrier in the river 2 Hochwasserstand HW Q0032_SLR0 KUKA-NSEE 1 Hochwasserstand HW Q0032_SLR0 KUKA-NSEE (seeEms figure 1). 3 HochwasserstandUTC HW Q0032_SLR1 KUKA-NSEE UTC UTC UTC UTC 4 Hochwasserstand HW Q0032_SLR0 KUKA-NSEE 2 Hochwasserstand HW Q0032_SLR0 KUKA-NSEE Ems 5 HochwasserstandEms HW Q0032_SLR0 KUKA-NSEE USER: BAW-AK (ReferatK3) FILE: gview2d0012.cgm 6 Hochwasserstand HW Q0032_SLR1 KUKA-NSEE 3 Hochwasserstand HW Q0032_SLR1 KUKA-NSEE SLR=1 Hochwasserstand 0cm, closed storm surge HW barrier Q0032_SLR0 KUKA-NSEE4 Hochwasserstand HW Q0032_SLR0 KUKA-NSEE Programm GVIEW2D 14.06.2018 퐬퐭 SLR= 0cm, open storm surge barrier Enhancing the flood from ퟏ November 2006 Ems SLR=2 Hochwasserstand 50cm, closed storm surge HW barrierQ0032_SLR0 KUKA-NSEESLR=5 Hochwasserstand 50cm, open storm surge HW barrier Q0032_SLR0 KUKA-NSEE SLR=100cm,3 Hochwasserstand closed storm surge HW barrierQ0032_SLR1 KUKA-NSEESLR=100cm,6 Hochwasserstand open storm surge HW barrier Q0032_SLR1 KUKA-NSEE m By increasing the water level at the open boundary to the North Sea two sea level 6.5 4 Hochwasserstand HW Q0032_SLR0 KUKA-NSEE rise scenarios are simulated (50cm and 100cm). Each scenario is modelled for an 5 Hochwasserstand HW Q0032_SLR0 KUKA-NSEE 6. 6 Hochwasserstand HW Q0032_SLR1 KUKA-NSEE open storm surge barrier and for a closed storm surge barrier in the Ems estuary. 5.5

Impact of sea level rise (SLR) 5. m 6 A sea level rise leads to an increase of highest water levels during storm surge 4.5 3 6.5 throughout the entire Ems estuary. However, the exact amount of the increase 5 m 4. 2 varies spatially (see figures 5 & 6). Closing the storm surge barrier in the 6.5Ems cuts 3.5 4 6. off the impact of the sea level rise so that upstream water levels remain 1 3. unaffected (see figure 4). The closure of the storm surge barrier causes a 6. positive 2.5 5.5 surge leading to higher peak water levels downstream of the barrier. Upstream, 0 25000.0 50000.0 75000.0 1.000E5 1.250E5 Meter the protective function of the barrier leads to lower peak water levels 5.5 during Ems KM 107 Emshoern Emden Terborg Herbrum storm surge. Hubertgat 5. Dukegat Pogum Leerort Bollingerfaehr Borkum-Fb.1 d(Hochwasserstand HW) SLR050-000Knock KUKA-NSEE Ems-SPW Papenburg Ems_REFSF06 2 d(Hochwasserstand HW) SLR100-000 KUKA-NSEE USER: BAW-AK USER:BAW-AK (Referat K3) FILE: Lq2pro0010.cgm 푠푡 5. Fig. 4: Highest water levels during the flood from 1 6 November 2006 for differentProgramm sea LQ2PRO level 14.06.2018 rise (SLR) scenarios and 4.5 with open or closed3 storm surge barrier along a profile in the Ems estuary6

4.5 3 m 5 1.2 4. 2 1.1 5 2 4. 1. 2 0.9 3.5 4 1 0.8 3.5 4 0.7 1 0.6 3. 1 0.5 3. 0.4 0.3 1 Hochwasserstand 2.5 HW Q0032_SLR0 KUKA-NSEE Ems 0.2 250cm Hochwasserstand SLR – no SLR0 (open stormHW Q0032_SLR0surge barrier) 25000.0KUKA-NSEE 50000.0 75000.0 1.000E5 1.250E5 2.5 0.1 100cm3 Hochwasserstand SLR – no SLR (open stormHW Q0032_SLR1surge barrier) KUKA-NSEE Meter 0 4 Hochwasserstand HW Q0032_SLR0 KUKA-NSEE 0 0 25000.0525000.0 Hochwasserstand50000.0 HW Q0032_SLR050000.075000.0 KUKA-NSEE1.000E5 75000.0 1.250E5 1.000E5 1.250E5 Meter Fig. 6: Difference in highest storm surge water levels between a scenario with SLR = 100cm and a scenario without a 6 HochwasserstandEms KM 107 HW Q0032_SLR1 KUKA-NSEEEmshoern Emden Terborg Meter Herbrum Ems KM 107 Emshoern Emden Terborg Herbrum sea level rise (SLR). In both simulations the storm surge barrier in the Ems estuary is open. The black line denotes profile Hubertgat Dukegat Pogum Leerort Bollingerfaehr where highest water levels were evaluated Hubertgat Dukegat Pogum Leerort Bollingerfaehr

Ems KM 107 Borkum-Fb.Emshoern Knock Ems-SPW EmdenPapenburg Terborg Herbrum USER: BAW-AK USER:BAW-AK (Referat K3) FILE: Lq2pro0008.cgm Literature: Fig. 5: Difference in highest water levels during stormBorkum-Fb. surge between scenariosProgramm with LQ2PRO and 14.06.2018 Knock Ems-SPW Papenburg Casulli, V. (2008) A high-resolution wetting and drying algorithm for free-surface hydrodynamics. Int. J. Numer. Meth. Fluids. DOI: Hubertgat without sea level rise (SLR) alongDukegat a profile in the Ems estuary Pogum Leerort Bollingerfaehr

10.1002/fld.1896 USER:BAW-AK (Referat K3) FILE: Lq2pro0010.cgm Programm LQ2PRO 14.06.2018 m Borkum-Fb. Knock Ems-SPW Papenburg

July 2018 · Contact: Tabea Brodhagen · Department of Hydraulic Engineering 6.5 in Coastal Areas · Tel.: +49(40) 81908-458 · [email protected] USER: BAW-AK USER:BAW-AK (Referat K3) FILE: Lq2pro0010.cgm Programm LQ2PRO 14.06.2018

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2.5 0 25000.0 50000.0 75000.0 1.000E5 1.250E5 Meter Ems KM 107 Emshoern Emden Terborg Herbrum Hubertgat Dukegat Pogum Leerort Bollingerfaehr

Borkum-Fb. Knock Ems-SPW Papenburg USER: BAW-AK USER:BAW-AK (Referat K3) FILE: Lq2pro0010.cgm Programm LQ2PRO 14.06.2018