12 December 2001
SITE CHARACTERIZATION AND DESIGN CRITERIA. Many coastal
failures can be traced back to inadequate site characterization analysis. Site
characterization involves identifying distinguishing qualities and features of a region that
have a direct and indirect impact on the conception, design, economics, aesthetics,
construction and maintenance of a coastal project. The coastal environment varies
spatially and temporally and therefore a design that is functionally, economically, and
environmentally appropriate at one location may be inappropriate at another. Physical,
biological, and cultural attributes need to be delineated so that an acceptable project is
adopted and potential effects of the project are determined. Sections V-2 and VI-3 of
the CEM cover this topic in detail.
Hydrographic Surveys and Subbottom Profiling. It is important to
perform surveys to identify bottom conditions and to determine if any structures are
present which need to removed or avoided. This knowledge pertains to both
construction efforts and dredging. Table 5-2 provides information on some of the
bathymetric, Differential Global Positioning System (DGPS), and sidescan sonar
sources available to the design engineer.
PORT AND HARBOR PROJECT DESIGN - DREDGING AND
NAVIGATION PROJECTS. Planning efforts must consider environmental policies
such as the National Environmental Policy Act (NEPA), the Environmental Assessment
(EA), and the Environmental Impact Statement (EIS). Project Assessment and
Alternative Selection, and Development of a Navigation Project, are addressed in the
Project Assessment and Alternative Selection. This information is
readily available from the CEM, Section V-5, which acts as a complement to EM 1110-
2-1613, Hydraulic Design Guidance for Deep-Draft Navigation Projects and EM 1110-2-
1615, Hydraulic Design of Small Boat Harbors.
General Harbor and Port Facility Issues. Within limits, any site may be
modified to accommodate the required vessel use. Ideally, the minimum and maximum
area requirements must be estimated in order to properly evaluate a proposed location.
For military purposes, it is desirable to allow for unrestricted operation of all vessels at
all times. However, it is not always practical to design for statistically infrequent low-
water conditions or an all-weather navigable entrance at locations exposed to extreme
wave climates. Before proceeding with the design, trade-offs based upon the
probabilities of occurrences should be discussed with the using agency.
Major Water-Area Elements. Figure 5-1 illustrates the arrangement of
major water-area elements associated with a harbor facility. Depending upon siting, a
harbor facility may include all of, or portions of, these elements. Functionally,
approach- and entrance-channel elements provide the transition between open-sea and
protected water environments. The protected interior channel serves as a navigational
linkage; in riverine situations, this channel length can become of increasing importance.
Turning basins provide area for a ship to maneuver while approaching its final terminus,
either alongside berths or in open mooring areas. In some harbors, special water areas