Storm surges

Question 1

Definition Storm Surge

Answer 1

combination of storm (u>80km/h) and flood (high water levels)
=> high water levels due to severe winds

Question 2

Schleswig-Holstein storm surge classifications

Answer 2

Storm surge: 1,5 - 2,5 m ü. MHW (WC) / 1,5 - 2,0 m ü. NN (EC)
Severe storm surge: 2,5 - 3,5 m ü. MHW (WC) / 2,0 - 2,5 m ü. NN (EC)
Heavy storm surge: >3 m ü. MHW (WC) / >2,5 m ü. NN (EC)

Question 3

Physical Processes of Storm Surge Formation

Answer 3

• Meteorological influences
• Astronomical tides
• External surges
• Headwater influence

Question 4

Short-term influencing factors

Answer 4

-Tidal waves (Astronomic tide)
-Wind surge (dominating!!) (“meteorological tide”(hard to predict))
-external surges (“meteorological tide”(hard to predict))
-basin oscillations (Seiches…) (“meteorological tide”(hard to predict))
-headwater inflow Q0 (“meteorological tide”(hard to predict))

Question 5

Long-term influencing factors

Answer 5

-Secular sea level rise and land subsidence
-constructional interventions
-morphological changes

Question 6

Storm Paths of Important Cyclones

Answer 6

-Jutland type:
Low which forms over Newfoundland, moves over central England into the North Sea going east or southeast and then crosses Jutland
(e.g. 03.01.1976).

-Skagerrak type:
Crossing the North Sea andSkagerrak west-northwest to east-southeast (e.g. 10.10.1926)

-Scandinavian type:
Forms over Greenland and Iceland, moving southeast over the North Sea (e.g. 17.02.1962).

Question 7

what landward and seaward slopes do dikes generally have nowadays?

Answer 7

Seaward: 1:4 - 1:7
Landward: 1:3 - 1:5

Question 8

Wind-induced water level increases are influenced by …

Answer 8

-the strike length of the wind
-the density of water and air
-the water level
-the wind velocity

Question 9

which factors get taken into account for the determination of stormtide water level for the design of dikes?

Answer 9

-MHW
-spring tide
-wind surge
-secular sea level rise