EM 1110-2-1100 (Part II)
30 Apr 02
Example Problem II-8-2 (Continued)
The combined effect of tide and storm surge for the first event (excluding wave setup) at the jetty head and
nearshore (shallowest) trunk segment are given in Table II-8-15. These initial depth estimates are referenced as
dijettyA for the head and dijettyC for the nearshore trunk segment. Similarly, combined tide and storm surge levels are
computed for each of the 33 storm events at the three jetty design segments.
Table II-8-15
Calculation of dijetty for Storm Event 1
Water Level Exceedance Frequency (percent)
Water Level
90
70
50
30
10
Storm surge (m)
0.7
0.7
0.7
0.7
0.7
Jetty Head
Tidal water depth (m)
11.9
12.1
12.3
12.5
12.8
dijettyA (m)
12.6
12.8
13.0
13.2
13.5
Nearshore Jetty Trunk
Tidal water depth (m)
3.9
4.1
4.3
4.5
4.8
dijettyC (m)
4.6
4.8
5.0
5.2
5.5
Inclusion of wave setup. The effect of wave setup on water levels at the jetty can now be considered. Calculation
steps are listed below and results for Event 1 at the jetty head and nearshore jetty trunk segment are given in
Table II-8-16.
(1) Retrieve H0N/L0 from Table II-8-13.
(2) Calculate dijetty/H0'.
(3) Estimate ratio of wave setup η to H0' from Figure II-8-24.
(4) Calculate η from ratio in step (3). If η is less than zero, a value of zero should be used for prudent
design.
(5) Calculate a final djetty as the sum of and the previous dijetty, which included only tide and storm surge.
η
If η is large, it may be necessary to return to step (1) using djetty in place of dijetty and repeat steps (1) through (5).
Example Problem II-8-2 (Sheet 10 of 21)
II-8-44
Hydrodynamic Analysis and Design Conditions
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