Savannah morning news. [volume] (Savannah) 1868-1887, 1884-12-07
JETTIES DOING THE WORK
THE HARBOR IMPROVED BY
GOVERNMENT OPERATIONS.

The Jetty System and What it Contem-
Plates-The Work Generally Approved
by River Men-The Channel Deepened
from Five to Eight Feet-What the
Pilots and Steamship u en- Say-Causes
of the Shoals Along the City Front.
For some time past a disposition has
been manifested in some circles to criti-
else the work Of the government engineers
in the Savannah river, and statements
have been made that the system of jetties
being constructed would be more of de-
triment to the stream than a benefit. 1t
was also stated that it had been charged
that the work of the engineers would
eventually result in running the channel,
although the source of this declaration
could not be learned. All of the state
ments rejecting upon the work have been
of an indefinite nature with the exception
of the drawing up of a petition for the
pilots and others to sign, stating that the
work would ruin the channel, and asking
that it be suspended. This was some time
ago, and the paper received very few sig
natures, one pilot, it is stated, appending
his name.
An inquiry into the matter, conducted
with some care, and including in its scope
pilots, captains of coastwise steamships,
the agents of the Baltimore, New York,
Philadelphia and Boston ships, and the
government engineers themselves, shows
that the complaints made are not borne
out by facts. The plans of the engi-
neers contemplate giving Savannah river,
when completed, depth of % feet. This,
as the public Knows is to be done by means
of a system of jetties, number of which
have already been completed, by which
the current is to be contracted the in
8 oz1,n 81
securing out the accumulatiOns on the bot
tom and deepening it. Wherever these jet
ties, or wing dams, have been construct
ed along the river the channel has been
deepened. On the authority of the United
States Engineer it is stated that this IN
crease in depth has been from to s feet.
Between the constructed dams at the up
per flats depths have been increased from
10 and u to 10 and Is feet mean low water.
other places along the river.
OBJECTIONS TO THE WORK.
What has given some cause for COM
plant has been the forming of new bars
or shoals below the jetties. This fOrma-
ton is a perfectly natural result in the
progress of the work. The construction
of a jetty on either side of a sand bar so
that the contracted current would sweep
directly over it would result in the scour-
much of this dislOdged material is carried
further down the stream and again settles,
forming a new bar or increasing the
height of an old one. The construction of
a lefty further down sweeps this new bar
further out toward sea and so on
until there is clear and unobstructed
channel. This shifting of shoals is the
only drawback in the work, except that
the steamboat captains claim that the
narrowing of the channel and the extend
ing of the jetties has made the river
harder to navigate, while sailing vessels
now find it almost impossible to beat their
way up stream.
NOT AN EXPERIMENT.
The erroneous impression that the work
now being done in Savannah river was an
experiment, so far as jettying d tidal
stream zone in which the tide both GIBBS
and fiOws) was concerned, has caused
some to look with uneasiness and sus-
piciOn upon the work. 1t is a mistake to
suppose that streams like the Mississippi,
in which there is practically no tide, are
the only ones in which the jetty system
has been successfully tried The
channel of the river Clyde, which
is similar in its natural condi-
tions to the Savannah, was deepened
in the same way with spur jetties extend
ing out into the stream, and afterwards
with trailing dams or jetties, extending
along either side of the channel and con-
Meeting the outer ends of the spur jetties.
The following cut will readily explain the
system to landsmen, who are not familiar
with work Of this kind: