Coastal Engineering 52 (2005) 285 302
www.elsevier.com/locate/coastaleng
Prediction of swash motion and run-up including the effects of
swash interaction
Li Erikson*, Magnus Larson, Hans Hanson
Department of Water Resources Engineering, Lund University, Box 188, 221 00, Lund, Sweden
Received 5 February 2004; received in revised form 4 May 2004; accepted 14 December 2004
Abstract
Modifications to a model describing swash motion based on solutions to the non-linear shallow water equations were made
to account for interaction between up-rush and back-wash at the still water shoreline and within the swash zone. Inputs to the
model are wave heights and arrival times at the still water shoreline. The model was tested against wave groups representing
idealized vessel-generated wave trains run in a small wave tank experiment. Accounting for swash interaction markedly
improved results with respect to the maximum run-up length for cases with rather gentle foreshore slopes (tanb=0.07). For the
case with a steep foreshore slope (tanb=0.20) there was very little improvement compared to model results if swash interaction
was not accounted for. In addition, an equation was developed to predict the onset and degree of swash interaction including the