EM 1110-2-1100 (Part II)
30 Apr 02
Example Problem II-8-2 (Continued)
Estimation of shoaling coefficient (Goda 1985)
Combined tide and storm surge for design wave analysis at jetty. For design
wave analysis, extreme combinations
of tide, storm surge, and waves must be considered. Since extreme storm surge and waves are often highly
correlated (both can be produced by intense storms), they should not be treated as independent processes. The
relationship between storm surge and waves is embodied in the available measurements to an extreme occurrence
of approximately once in 17 years.
For this example problem, combined tide, storm surge, and waves for design analysis are derived by the following
approach. Each measured wave and surge event (represented by H0', Tp, and storm surge height) is coupled with
N high tide levels taken from the probability distribution of high tides (see Table B-37b in Harris (1981)).
(Figure II-8-23 is a partial extraction of Table B-37b for use in this example). As before, it is assumed that the
duration of extreme storm surge events is long enough that peak surge will coincide with a high tide, and high tide
level is independent of storm surge level. The N high tide levels are determined by dividing the probability
distribution of high tides into N equal probability increments and taking the tide level for the mid-probability of
each increment. The number N should be large enough that the combined probability of the highest tide level and
the most severe surge/wave event is lower than the design probability.
Example Problem II-8-2 (Sheet 7 of 21)
Hydrodynamic Analysis and Design Conditions