Modeled run-up

L. Erikson et al. / Coastal Engineering 52 (2005) 285302

295

0.042

Fig. 6. Measured run-up lengths (dashed lines) and swash depths at the initial still water shoreline (solid lines). Bore heights and arrival times

input to model are shown with downward pointing triangles. (N.B. Vertical scale differs between panels).

maximum run-up heights are substantially different

depth precedes the variation of the run-up. This is

for cases B8 through B10 depending on whether

important as the measurements taken at the SWS

swash interaction is accounted for or not, the vertical

contain some part of the run-up signal due to the

scales in Figs. 9 and 10 are not consistent for a given

backwater returning to the SWS. It is also apparent

case. If the vertical scales were the same, much detail

from the peaks of the curves, shown with the solid

between measured and calculated run-up lengths

circles on the inset of the figure, that there is a phase

would not be visible in Fig. 9. Inputs to the model

shift of less than half a second between the run-up and

are bore heights and their arrival time at the SWS. The

swash depth at the SWS. Furthermore, there is a

bore heights and arrival times at the SWS are taken at

negative correlation between the phase shift and

the peaks of the time series in Fig. 6 as depicted by the

incident wave period so that the greater the incident

downward facing triangles. Up-rush leading edge

wave period, the shorter the phase lag.

heights (yhu) were estimated by iteration of the

5.2. Modeled run-up

empirical equation presented by Hughes (Eqs. (19)

and (20), 1992):

In Fig. 9, measured run-up lengths are compared to

yhu h4zm

14

s

run-up lengths calculated with the model described in

2

where h*=0.210.48x*+0.32x* and x* is the dimen-

Section 3. Model results without accounting for swash

s

interaction are shown in Fig. 10. Because the

sionless distance from the initial shoreline position to