of the Freeport jetties which have received only minor repairs since the
1940's. The possibility of project modifications at Freeport has delayed
jetty rehabilitation.
1 1 . Design of the structures during the past 25 years is based on
various engineering memorandums and Coastal Engineering Researcn Center
(CERC) publications, in addition to the experience gained from construction
and maintenance of the existing structures. Selection of armor stone size
and slope i based on Hudson's slope stability formula. For the gulf coast
s
wave climate, stability coefficients used in designs typically are above zero
damage levels, resulting in a nonconservative design at the structures' sea-
ward ends but considered adequate in light of past experience and additional
costs required for a fully stable design. Design wave heights and maximum
surge levels are typically determined from historical hurricane events,
observed wind and tide data, and an expected 50- to 100-year storm recurrence
interval. Design wave heights are depth-limited in regions where they exceed
0.78 times the water depth. Actual wave data were not used in any design, and
it is not known whether any useful data exist. Although no model studies have
been conducted on stability of structure cross sections, p r o t o t y p e data were
and functional
collected and analyzed for Port Mansfield (Kieslich
hydraulic model studies were conducted for Galveston (Simmons and Boland 1969)
and Matagorda (Rhodes and Simmons 1 6 )
96.
12. Case histories of the structures for each project are included in
Pertinent summary information on each project i presented in
s
Tables
the following listing.
1
0
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