Year: 1876




THE MISSISSIPPI JETTIEs.


Rapid and Satisfactory Progress of TIA,
| Great Work.


The New Orleans Times of March Is


says: Last Saturday evening, before the


steamer Martha left on her usual Satur
| davis excursion to Port Eads, Pilor
| Town and other points of interest at the


passes, q large party of prominent gen
! tlemen from ST. Louis, Cincinnati anC
| Pittsburg, embarked on her and pro


ceeded down the river to ascertain the
progress of the works at the end o


South Pass.


After a minute inspection of the pro
cess of making mattresses of willow, anC


an interesting survey of important OBJ
] iects, with the distinguished engineer t6
explain everything iucidly, the party
slowly steamed down between the lons


sea walls In other letters your special


has described the progress of the pile


driving and mattress sinking, and il is
only necessary to say that this has been
| pushed as rapidly as possible. The mat
| tresses have been sunk in the east jetty
| beyond the crest of the bar, while 50 far
all the work on that sea wall has re-
mained solid, and grows firmer every day
as the deposit on the exterior side of the
work is rapidly covering it, as was ex-
pected or counted upon, and hence the
work is being set as solid as rock. On
| the western wall the work is being laid
from the outer end landmark. As far as
both walls have been completed the
depth between them has been increased
to from twenty-five to thirty feet, though
the attrition nearer the shore is necessa-
rily slower than further out on account
of the greater age and sohdity of the de-
post. From the land outward the chan
mel of the greatest depth has been cut
near the western wall; as the eastern
jetty being completed first DETECTED the
line of swift current as far down as the
work was completed enough to illustrate
practically the jetty theory, while toll
erably uniform and constantly increasing
depth has been obtained, making the
theory q settled axiom. As the boat
neared the crest of the bar, careful and
continuous lead heaving showed the in
crease of the depth to have been rapid
within the past few days. On the ar
rival at the crest OF the bar, which be-
fore the work was well commenced only
had seven feet of water, depth almost
incredible to all but the engineers in
charge was demonstrated to exist. As
the boat proceeded the line showed four
teen feet, sixteen and occasionally even
eighteen feet. With lead heaving at in
tervals less than one hundred feet apart
all the way across the bar in the channel
of the swiftest current, fourteen feet was
the least depth found. After going TO
deep water the vessel recrossed the bar.
In the channel mentioned again they
found the minimum depth to be fourteen
and maximum eighteen feet. The line
of the greatest depth was found to be
about two hundred feet east from and
parallel with the western wall, but ex-
tended far beyond the outer end OF that
jetty. On the results mentioned being
practically demonstrated, Capt. Basset
said he was satisfied a steamer could 90,
drawing fourteen feet of water, to sea
through this pass. Col. Andrews added
that eyes, and tomorrow he would guar
antee to take steam vessel drawing six
teen feet over" The first result of the
work, that of increasing the velocity of
the current to such degree as to enable
it to hold a greater amount of sediment
in suspension and to sever away the de-
posit, has been practically reached, and
the second of course follows as corrol-
larry event, which only needs very little
time to work out-that is to scOur out
enough mud to make the channel twenty
feet deep. The distinguished engineer
in charge stated to the party that within
four weeks depth of water of eighteen
feet across the bar before South Pass
would be fixed fact.


The velocity of the current in the pass
has already been increased to five and
six feet per second by running a wall of
willow mattresses nearly one thousand
yards long before Northeast Pass, to
force more water down South Pass. By
this increased current, another desired
end, the cutting away of the little island
in the head of the latter pass, is being
gradually accomplished. If necessary TO
concentrate still greater volume of wa
ter in the improved pass, it can be done
by such DETECTING walls at the head of
the pass at an expense comparatively
trifling to that required in the wall at
the sea end. In the present condition of
this great enterprise the parties most con-
cerned seem sanguine of achieving COM
plete success at date much earlier than
was expected a few days ago. With the
current now controlled by works not near
completion, and such results obtained by
only partially concentrating it on the
bar, it seems reasonable TO suppose that
by further concentration and depend
ent current velocity, from finished walls
impervious to a lateral flow, depth will
be obtained logically and actually far
greater than that required at the stipu-
lated time.