2008 REED’s East Coast Edition - Pilot Notes
Gulf Intracoastal Waterway
Tides: Under normal conditions the mean
range of tide in the waterway varies from a
The Gulf Intracoastal Waterway (also re-
constant level to roughly 3ft.
ferred to as the GIWW, ICW or “the ditch”)
Currents: A large number of rivers,
stretches across the Gulf Coast from Browns-
streams and dredged channels cross the
ville, Texas to Carrabelle, Florida. It crosses
GIWW. In most cases there is little notice-
bays and sounds and is often dug through
able impact on piloting. However, spring
shallows and farm fields. Maintained by the
floods can halt traffic completely where the t
US Army Corps of Engineers at a project
GIWW crosses the Mississippi River and
ilo
depth of 12ft for a width of 125ft, the GIWW
its flood control outlets. Local and seasonal P
is used extensively by commercial traffic car-
weather conditions can also cause difficulties
rying bulk liquid chemicals, construction
for low-powered vessels wishing to cross the
materials and agricultural commodities.
Brazos and Colorado Rivers in Texas.
While other vessels may be encountered,
Communications: Bridge-to-bridge com-
towboats pushing barges ahead of them are
munications are vital to safe piloting on the
most common.
GIWW. Tow boats may be draft constrained
Commercial traffic on the GIWW is heavi-
and may be otherwise restricted in their abil-
o
ast
est between Galveston Bay (the Houston-
ity to maneuver. Between Brownsville and
C
Galveston Ship Channel) and the Mississippi
Galveston Bay, use VHF 16. From Galveston
ulf
River at New Orleans, with a noticeable
Bay to the Mississippi River, VHF 13 is used,
G
reduction between Galveston Bay and Free-
with vessels changing back to channel 16 E
port, Texas, as well as E of New Orleans to
of New Orleans. Be aware that participation
Mobile Bay. The fewest commercial vessels
is mandatory for the USCG-operated Vessel
will be encountered on the run through the
Traffic Services on the Mississippi River and
Laguna Madre from Corpus Christi Bay S to
at Berwick Bay.
Port Isabel, Texas.
Bridges: Numerous highway and rail
Yachts are discouraged from transiting the
bridges cross the GIWW, with the majority
GIWW during darkness unless equipped
of the fixed variety. A few bascule and pon-
with dual-channel VHF radios (VHF 13/16),
toon bridges still exist. These may open on
radar, depthsounder and at least one power-
demand, have a schedule or restrict openings
ful spotlight. Navigational markers of any
during certain hours.
sort are few.
The minimum vertical clearance of bridges
It is not possible to anchor in or very near
and power lines to the east of Mobile Bay is
the GIWW, even under emergency condi-
generally 55ft, while to the west, 73ft clear-
tions. Pleasure boat facilities and anchorages
ance is the standard.
can be many miles apart and daily trip plan-
Locks and Floodgates: Along the GIWW
ning is required. Use of a detailed guidebook
in Louisiana and Texas, numerous locks and
is recommended.
floodgates exist to control saltwater intrusion
Mileage: All references to position on the
into freshwater agricultural irrigation sys-
GIWW are made by the statute mile distance
tems or promote navigation. Contact lock-
from Harvey Lock, on the west bank of the
masters on VHF 13 for instructions.
Mississippi River. From mile zero, distances
Buoyage: The U.S. Coast Guard maintains
are referred to as WHL (W of Harvey Lock)
the aids to navigation along the GIWW, as
or EHL (E of Harvey Lock). Signs with a
well as most navigable channels that cross it.
blue border are placed every 5sm where pos-
Standing navigational aids may be placed in
sible, corresponding to the magenta lines on
relatively shallow waters along the edge of
NOAA strip charts.
the channel. Extreme care should be exer-
Charts: The National Ocean Service pro-
cised if a close approach is necessary.
duces a series of charts, most in folio format,
Speed Limits: Speed limits and No Wake
covering the entire length of the GIWW.
zones will be found along the GIWW, partic-
Given the scarcity of customary aids to navi-
ularly near locks, floodgates and commercial
gation, these charts are a necessity for any-
facilities.
one piloting these waters.
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