TM 5-850-1
(1) Anchorage and berthing areas. For a given
(5) Upland drainage. Preferably the upland area
ship, the depth requirements at anchorage and berthing
shall be naturally well drained.
areas are the same.
Except where heavy silting
e. Hydrographic and hydrological factors.
conditions require greater depth, at individual berths at
low water, the depth should equal the maximum loaded
(1) Tidal range. Tidal range should be minimum.
draft of the largest vessel to be accommodated, plus 4
feet to protect the ship's condensers. For modern
container ships, a water depth of 40 feet is required.
(2) Bore. Locations with a tidal bore should be
avoided.
(2) Channels.
(3) Currents.
Current velocity should be
(a) Economic considerations can be
minimum.
Except for the localized area or special
weighed against depth requirements. In harbors where
considerations, should not exceed 4 knots.
the tidal range is very large and particularly where an
entrance channel is long, consider the possibility of
(4) Fouling rate. Site should have a low fouling
restricting the entrance of the largest ships using the
rate, be relatively free of marine borers, and have sufficient
harbor to the higher tidal stages.
water movement to remove contaminations.
(b) Where hard bottoms exist and
(5) Stable shorelines. Avoid locations having
excavation costs are high, consider the exclusion of
unstable shorelines or pronounced littoral drift. The history
certain classes of deep draft vessels, with provisions of
of erosion and deposition (shoreline changes) in the area
lighter service between deepwater anchorage and
should be thoroughly studied.
docks.
(6) Tributary streams. Location and depth of all
d. Physical and topographical features.
streams emptying into the harbor should be determined.
Depth and flow can be maintained in the final design to
(1) Sheltering from winds and ocean waves.
prevent a grading.
Natural sheltering features, such as headlands,
promontories, offshore shoals, and bars, will
f. Meteorological factors.
substantially reduce artificial sheltering requirements
(breakwaters) and overall project cost.
(1) Storm. Avoid locations subject to pronounced,
severe, and frequent storms.
(2) Bottom conditions. Clay or other firm-
tenacious materials furnish the best holding ground for
(2) Temperature. Ocean temperature should be
anchors. Avoid sites where the bottom does not provide
moderate to warm, and temperature range should be
suitable holding ground for anchors. When very hard or
moderate.
soft bottoms exist, costly provisions (mooring islands,
etc.) must be provided for securing ships.
(3) Fog. Avoid locations with a predominance of
fog.
(3) Dredging.
Sites requiring excessive
dredging of large quantities of rock or other hard
(4) Ice. Avoid locations that might be ice locked
bottoms should be avoided.
for several months a year.
(4) Shoreline relief.
Land adjacent to
g. Other factors.
shorelines can gradually slope away from the beach.
Avoid locations with pronounced topographic relief
(1) Availability
of
construction
materials.
(cliffs) adjacent to shoreline.
Determine the availability of construction materials,
particularly rock for breakwater and jetty construction.
(2) Freshwater availability. Ensure the availability
of a potable water supply.
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