The Bolivar bulletin. [volume] (Bolivar, Hardeman County, Tenn.) 1865-1888, 1875-05-28
What are Jetties?

The Scientific American gives
familiar description of the lefty system
which is to be applied in the improve
ments at the mouth of the Mississippi,
as follows:
The long discussion relative to the
most practicable method of improving
the mouth of the Mississippi, so as to rem
der the same passable to vessels of deep
draft and thus to open the river ports
terminated by the granting of an APP
preparation by congress, for the con-
strUction of a system of jetties, at one
of the passes through which the stream
enters the Gulf. The plans involving
canals, which have been strenuousIY
advocated by many eminent engineers,
are therefore for the time at least set
aside, and to Capt. J. L. Eads, an en-
gineer now widely celebrated for his
successful construction of the ST.
Louis bridge, has been entrusted the
task of causing the mighty current of
the father of waters literally to undo
its own work and to break down the
barrier which itself has created.
The delta of the Mississippi is formed
of narrow strips of land, mostly low lying
banks, through which the river winds
till it makes its exit to the gulf by a
number of narrow passes. In some of
these channels, previous attempts have
been made to deepen them by dredging,
with but partial success, however, as a
single flood has been known to carry
| down sufficient sediment to fill them to
| their original depth and the current
! besides, emptying into the open water
at the mouths, speedily left at that point
bars of blue clay, surmOuntable only
| by light draft ships. The gist of Capt.
| Eads' plan will now be readily appre-
hended when it is regarded as shifting
the point of deposit of these barriers
! from the shOal water at the entrance OF
one pass, out into the deep water where
| filling up by natural causes is impossi-
BILE. By this means the river current is
| to be made to cut out and scoUr its own
! channel across the present bar. To dc
this, it is obvious that the banks Of the
pass must be extended, so as to lead the
! stream far enough out another section
OF conduit, as 1t were, must be added,
and this is now to be formed of the
submarine dykes or ietties.
| The materials of which these struc-
| lures are to be composed are willow
| tWigs bound IN bundles, termed by en-
/ gineers g facines," eight or ten feet IN
/ length, and about as many inches In
diameter. a large number of facines
will be dashed together to form RATS.
! The RATS will be from seventy-five to
! two thousand feet in width, the largest
being sunk in the deepest water. The
RATS will next be tOwed to the proper
pc int, there loaded with stones and
submerged, and thus the work
will continue, one raft being sunl
above another until the surface
is reached. Each line of the raft
will be narrower than the one be
low it until the upper course will not b.
more than ten feet wide. The TIVE
which will thus be constructed viii b.
prOlOngatiOns of the banks, and be
tween them will form a channel will
sloping sides. In the course of time
the interstices of twigs and stones vii
fill with sand and mud, so that eventu
ally two solid submarine levees will b
produced. Very little pile work, it /
said, will be required except, perhaps
at the head of South Pass, which is tn
outlet at which the jetties are to b
built, IL order to provide for the prope
regulation of the volume of water i
the new channel at various stages c
the river.
Captain Eads has already begun hi
surveys, in which work, together wit
the making of the necessary contract
for materials, labor, ETC., the summe
will be consumed. The first raft, it
expected, will be sunk by the beginnin
of October next.