EM 1110-2-1100 (Part II)
30 Apr 02
Chapter II-7
Harbor Hydrodynamics
II-7-1. Introduction
a. A harbor is a sheltered part of a body of water deep enough to provide anchorage for ships or a place
of shelter; refuge. The purpose of a harbor is to provide safety for boats and ships at mooring or anchor and
to provide a place where upland activities can interface with waterborne activities. Harbors range in
complexity from the basic harbor of refuge, consisting of minimal or no upland support and only moderate
protective anchorage from storm waves to the most complex, consisting of commercial port facilities,
recreational marinas, and fuel docks linked to the sea through extensive navigation channels and protective
navigation structures. Key features of all harbors include shelter from both long- and short-period open ocean
waves, easy and safe access to the ocean in all types of weather, adequate depth and maneuvering room within
the harbor, shelter from storm winds, and minimal navigation channel dredging.
b. Harbors can be classified according to location relative to the shoreline or coast. Figure II-7-1
illustrates six harbor classifications. The inland basin and offshore basin require considerable construction,
including protective navigation structures and harbor and channel dredging to provide adequate protection.
They are usually constructed where no natural features exist but where a facility is required. Examples of
such harbors are Port Canaveral, Florida, Marina del Rey, California (inland basin), and Gulfport, Mississippi.
c. The natural geography can provide partial protection or headlands that can be augmented to construct
a protective harbor. This approach may reduce the initial costs of construction. Examples of such harbors
are Half Moon Bay Harbor, California; and Barcelona Harbor, New York (bay indentation); Crescent City
Harbor, California; and Palm Beach Harbor, Florida (offshore island).
d. In some locations, the land can provide protective harbors requiring minimal modification. Examples
include inside estuaries and up rivers such as at Panama City Harbor, Florida; Kings Bay, Georgia, (natural
harbor); Port of Portland, Oregon; and New Orleans, Louisiana (river harbor).
e. The U.S. Army Corps of Engineers has constructed hundreds of harbor projects that include
protective structures such as breakwaters, jetties, and navigation channels. Projects are classified by depth
and range from deep-draft projects with navigation channel depths greater than -45 ft, to intermediate-depth
projects with depths between -20 ft and -45 ft, to shallow-draft projects with depths less than -20 ft.
Currently, USACE operates and maintains over 25,000 miles of navigation channels in association with
hundreds of harbor projects.
f. This chapter covers basic harbor hydrodynamics. Harbor design is covered in Part V. The chapter
covers wave diffraction, wave transmission and reflection, harbor oscillations, flushing and circulation, and
vessel interactions. These are important elements that must be understood in order to design a safe harbor
that is operationally efficient.
Harbor Hydrodynamics
II-7-1
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