EM 1110-2-1100 (Part II)
30 Apr 02
Example Problem II-8-2 (Continued)
(3) For each selected event, subtract the predicted astronomical tide and wave setup from measured water
levels. The maximum difference during the event is considered the peak surge. Details of calculating
wave setup are omitted here but discussed later in conjunction with wave analysis.
(4) Organize peak surges into a probability distribution. The ACES Extremal Significant Wave Height
Analysis (using water levels in place of significant heights) may be a helpful tool for this and the
(5) Fit a probability distribution function to the data to extrapolate to lower probabilities as needed.
Probability distribution of storm surge
Combined tide and storm surge. A simplified analysis is used here to generate probabilities for combined tide and
storm surge. With consideration of general knowledge about the duration of storms, typical storm surge
hydrographs, and tidal variations at the site, it is reasonable (but somewhat conservative) to assume that peak water
level events can be represented as the measured peak surges coinciding with a high tide.
Example Problem II-9-2 (Sheet 3 of 21)
Hydrodynamic Analysis and Design Conditions