New Orleans Republican., 1875-11-23

| Iuohtus OF actual operations, that the work
OF pile driving, extending from the east
lands end to twenty-six feet depth beyond
the bar crest along line two and quarter
miles IN length, covering nearly the whole
| length OF the eastern .ietty, and an examiua-
| tlon OF the texture OF the bar and of the
shoals on which the works are to rest, fur
nlsh the most satisfactory evidence of a
bottom material not only adequate to bear
| all the necessary works, but even to sug-
gest that but for motives Of economy tquaI-
RES being tar distant) the jetties, as at the
Sullna mouth Of the Danube, might be
made wholly of stone. The commission,
therefore, unhesitatingly announce that the
supposed or attributed engineering difficult
ties OF construction OF engineering works at
the South Pass of the Mississippi as de-
pendlng on peculiarities of the Mississippi
| uelta, are illusory.
In fact, the execution of the works is far
! legs difficult than that of several recent sue
cesstul works of the kind on European
| shores, known to, and examined by the
members OF the commission. This facility
| OF execution arises, in q measure, from the
| fact that the broad, lateral shoals, almost
bare at low water, which extend seaw aid
from the lands ends, marginal TO the chan
mel, form very good protection to the pro-
| posed works, and almost reduce them to the
grade OF mere river works until the out 4r
| edge of the bar is reac d. The deep water
| poA tiOhri outoluC LILO Il VI lut proposed
| jetties, are comparatively short. While
these portions must have the dimensions
and strength of exposed sea works, they
offer no difficulty not common TO other
similarly exposed works now existing.
1t would seem proper, in this connection,
to say few words as - the South Pass
itself, in reference to its capabilities to fur
nish an open mouth to the main stream,
and thus form an adequate connection be.
tween the sea and tue 30 900 miles of inland
navigation which ramify from the river.
The South Pass is the middle one of three
| great passee, into which the river, after
having, for many hundred miles, rolled in
| single channel, divides a few miles before
! it finally discharges its waters into the Gulf
| of Mexico.
1t is but twelve miles long, being the
| shortest of the passes. From its point of
division, it carries its waters in channel
| everywhere five fathoms or more in depth,
with straightness of course and a uni,
| formity OF section and depth such as almost
to suggest to the voyager that he is navi-
| eating canal of unparalleled dimensions,
| OF width averaging 200 feet, sufficient for
| the convenient transit of the largest sea-
| going ships and of the congeries of yes
sells which constitute tow tor the power
| full tug boats in use. No sharp bend, no
! shoal, no reef, embarrasses it's navigation.
At the origin-the head of the passes-a
shoal indeed lies in advance of its entrance.
| ibis shoal has, however, a natural depth
equal TO that over the bar at Southwest
| Pass, and the commission anticipates no
serious difficulty in efecting over it the
required depth. From this point the
adequacy of depth continues unbroken
| for ten miles, till the seaward ex-
tremities of the land margins THE
natural jetties which thus far maintain
| it, are reached. Here released from
| confinement, the current ditflses itself: the
depth diminishes, until at TWO miles further
| tabout) the bar. having but seven feet
depth, is reached; beyond which, seaward
| depths of six, twelve, twenty four and more
fathOms are found in quick succession The
specific engineering work which the govern
ment of the United States has COM united TO
| Mr.. Eads Is by the well known method of
| jetties Tor otherwise) called ''parallel piers"
10 supply artiticially throughout this two
miles from the lands ends to the outer slope
of the bar the confning barriers which
| snail pr0long TO the sea the uniformity of
section and depth which the natural bar
riers for the preceding ten miles have Sc
| cured.
This is not the place to discuss the alb
| stract merits of a well llknown method
| which has elsewhere, in reference to its ap-
plication here, been thoroughly discussed
and disposed of, and in which the individ.
| ual members OF the commission have had
each one his own part to take. What has
been said in former paragraphs suffices to
| exhibit the strengthened confidence with
| which personal examinations of the spot
and OF the works now in progress has I'M
bued the members of the commission.
The commission considers the present an
| opportune moment to record it's opinion.
First, that the physical characteristics of
the Delta and bars of the Mississippi and
Danube are similar in many important re-
| spects; and secondly, that owing to the
| greater sea depth Immediately beyond the
| crest Of it's bar, to the existence of tide
water, to the apparent greater abrading
forces along the coast, and to the extreme
fnenees of the sand of which the bar is COM
posed, the mouth of the South Pass of the
Mississippi ls more susceptible of successful
| improvement, notwithstanding the greater
turbldity OF its tiuvial current, than was
the Sulina mouth of the Danube, when, IN
1888, the construction of the parallel piers
was commenced which secured to the navi-
cation of that river depth of seventeen
and half feet in 1861, and OF twenty and
half feet at the present time, or five feet
more than the works were originally de-
signed to obtain; and this at the mouth of a
river arm discharging less than one-third of
the volume OF water discharged by the
South Pass.
We now turn to the works actually at
this time executed by the grantee, Mr..
James Is. Eads, under the act of Congress
authorizing him to improve the South Pass
OF the Mississippi river, and we find that
they have been laid out and thus far carried
on substantially in accordance with the
plans submitted to and approved BY this
commission at the time of their session in
September last.
Considering that only the short period of
tive months has elapsed since the beginning
of operations at the South Pass, we are
struck with the amount of work which has
been accomplished; and although much that
has been done is provisional, to be supple
mented by other work, it is all necessary
and conducive to the end in view, which is
permanently to contine the flow within the
space OF 1000 feet between the crests of the
jetties.
We find from the records of the pile
driving, and from the manner in which the
piles have thus far withstood the action of
the waves and currents, that the material
OF the bar is even more solid than we had
ventured to anticipate it would be. As we
have already remarked we do not enter
tain any doubt as to the efficiency and per-
manency of the jetties, when they shall
have been completed upon the location and
plans heretofore approved by this commits
sion. 1t the arrangements made by the
contractors, Messrs. James Andrews & Co.,
for the early delivery of additional large
quantities OF stone for weightipg the mat.
tresses and for the protection of the ietties
against the action of the sea, are success
fully executed, we see no reason for doubt
ing the realization of definite and perma
nent good results at an early date.
1t is hardly within our province, if it were
even in our power, to offer any specific
opinion respecting the period when a given
depth across the bar may be reliably calcu-