Modelling Coastline Change of the Darss-Zingst Peninsula with Sedsim - The Baltic Sea Basin - page 292

eustatic scenario proposed within this study suggests otherwise. There is no evi-
dence that the wave system will change because of such a stationary process. We
assume the wave regime to be stationary, too. This is in contradiction to model
results from Grabemann and Weisse ( 2008 ) who detected a significant increase of
the wave heights because of future climate change. However, these results have been
acquired on behalf of the North Sea as a model region, and there is no equivalent
application for our area of interest.

14.4.6 Events

The wave data described in the previous chapter contains information about wave
heights, but because of the seasonal averaging extreme wave heights accompanied
with short-time storm events have to be added separately. The surges caused by
storms are crucial for the coastline development. Suddenly, previously safe onshore
areas are exposed to the forces of rising sea water, often resulting in dramatic coastal
erosion. For the coast of the study area the statistics in Table 14.2 clarifies return
frequencies for different surge types.
For the experiments with Sedsim, the STORMS module was set up with a dis-
tribution of storms occurring every second year with an increase of the sea level by
1 m and an additional significant wave height of 2 m. Actually, there is no overall
agreement whether frequency or intensity will change in the future (BACC 2008 ) .
According to Weisse and Storch ( 2009 ) studies on this matter always have a strong
regional form and may not be generalized. For the area of investigation no detailed
study about changes in surge statistics is applicable; therefore, a linear extrapolation
seems reasonable at least.
With the rise of the sea level during storms, onshore sediments are included in
the modelling of the erosion, transport, and accumulation. Also, a corresponding
shift of the wave base is taken into consideration.
The most devastating storm surge at the coast of Mecklenburg-Vorpommern ever
recorded and measured in detail was in 1872, during the night from the 12th to
the 13th of November. Locally, the height of the sea level reached over 3 m above
normal sea level. Today, this surge is considered as a benchmark for determining
the defence level for coastal protection. A reconstruction of the behaviour of the sea
level caused by this event was modelled by the Federal Office for Navigation and
Hydrography, Germany (Rosenhagen and Bork 2009 ) . In the area of investigation

Table 14.2 Return frequency
for different storm surge
types at the coast of
Mecklenburg-Vorpommern.
Modified after Hupfer et al.
( 2003 )

Sea level height above
normal sea level (m)

Return frequency
(years) Surge type

Light 1.00-1.25 1-2

Medium 1.25-1.50 5-10

Heavy 1.50-2.00 5-20

Very heavy > 2.00 50-100