Author(s): Stephan Mai; Nicole Von Lieberman; Claus Zimmermann
Linked Author(s):
Keywords: Wave transmission; Brushwood fences; Summer dikes; Physical andnumerical modelling
Abstract: The protection system of the German North-Sea coast comprises a series of elements with the dike supplying the main protection. Brushwood fences and summer dikes (submerged dikes) are applied in front of dikes as additional protection element. Apart from their original function for land reclamation and protection of reclaimed land against summer storm tides both, brushwood fences and summer dikes, cause a reduction of energy of the incoming waves and therefore of wave run-up at the main dike. The wave reduction, i. e. the transmission coefficients, depending on waterlevel, incoming wave and design parameter of the protection elements was investigated in the wave tanks of the Franzius-Institut, Hannover, Germany. Transmission coefficients are described in good agreement with empirical formulas for permeable and impermeable breakwaters depending on freeboard and wave steepness. Numerical modelling of the transmission process at summer dikes on the basis of energy decrease due to wave breaking according to Battjes and Janssen using phase averaged wave models showed good agreement with results from physical modelling.
Year: 1999