Southern sentinel. [volume] (Plaquemine, Parish of Iberville [La.]) 1848-1858, 1857-03-07
From the New Orleans Crescent.
Closing of Bayou Plaquoninc.
NEW ORLEANS, rep. 70, 1897.

~ bAShA t"O SNhNS
advocating the opening of new outlets, and
opposing the closing of the Bayou Plaque
mine.
The proposition for closing the Plaquemine
meets with favor from many Of our Oldest,
most intelligent and most experienced cltis
zens and many Of our best engineers have
been and are Of the opinion that no injury
whatever, 10 the river below, would result.
The writer believes it TO be demonstrable that
overflow could not possibly result, and is cons
fdent that every known fact, and all expe-
rience, is opposed to such 4 conclusion. The
writer proposes to review so much of Mr..
Hebert's report as relates 10 the question of
outlets. The State Engineer refers to Mr..
Ellet's paper on the Mississippi, in tones of
high commentator. / would therefore call
attention to an article of my own, in review
| of Mr.: Ellet, published in DeBow's Review
for August, 1852. Like Mr.. Hebert, 81 will
not pretend to lay claim TO originality in my
views;3' many Of our most talented engineers
have arrived at conclusions similar to my own.
| will only claim to have studied and invests
gated the subject thoroughly, and to have been
governed only by these Investigations. Mr..
Hebert says (on page l5) that " the rise and
fall of the river increases gradually from the
Gulf to the Ohio. At New Orleans it is some
Is feet; at Baton Rouge some 80 feet at
Helena about 10 feet, and so on" This does
not convey precisely the true idea. At the
mouth of Red River the rise is about as feet,
and thence to the Ohio the rise is everywhere
about fhe same or, from Is TO so feet. Ab0ue
Red River, shoals occur at intervals. Bet0W
Red River the character of the river is very
different; it is very deep even a: low water,
and the total rise and fall diminishes regularly
F-op, tho mouth ~ paG Pivnr 70 tho Gulf
Mr.. II. admits (page l6) that the first set
tiers along the Mississippi found rich lands
annually Cor nearly SOY overlooked by the
river" also " numerous outlets ;" aud else.
where that ali these outlets excepting the
Atchafalaya, Plaquemine and Lafourche, have
been closed also, that levees have been ex-
tended to and into Missouri; but, he says (on
page 49, " that now IN pieces where thore was
sufficient protection afforded by iegees of one
and two feet in height, we require leyees OF
six, seven or eight feet" ! admit that " in
places" this has occurred, but only in the
bends where the river has cut away and en-
eroached upon the high or front lands. This
is mol the case on the points, or on straight
reaches, where this front high land has not
caved in, and where The original levee yet ex-.
its. Here we find the levee of the same height
as at first. Ample evidence can he obtained
to prove this, even in the vicinity of Baton
Rouge. Inasmuch as the land slopes back
from the river everywhere, il follows Of course
that where the river encroaehes upon its
banks, each new levee has TO be made higher
and higher, rs they are built further and
further back; not because the river rises
higher, but because the land becomes l0lger at
The site Of each new .leYee. There is no
remedy for this except m efficient levee sys-
fnVl and y division of tho lurInn in maintain. |
ing leyees.
q Outlet or no outlet, the river will always cut
away its banks, for it did so when there were
no levees at all aud unless we are prepared
TO surrender The whole of Louisiana Che allu-
vion) ] can see no remedy but good levees, inI
place of the imperfect ones generally built.
assert, and q series of cross sections at
different stages of water, from high to low,
(taken at the same point and from established
zeros at high water mark in each case,) will
test the truth or falsity of my position, that
the channel Of the Mississippi, or rather the
area of its cross. section, changes aeih ecery
change in The heisAth Of Tie riter that it is
much less at low than at high water; that it
diminishes by deposit as the river falls that
it increases as the river rises, and that the
equilibrium between The size of channel and
quantity of water passing is always MAIN
tanned, at each and every stage of water. This
securing out progresses as the, river rises, and,
if an outlet has been closed during low water,
this securing goes on q little further below
said outletttan before. If an outlet has been
opened during low water this securing ceases
sooner, so that'in. every case, (and seventy to
one hundred years experience proves it, no
change whatever results to the heigbth or
plane of descent, consequent upon the opening
or closing of outlets. When outlets are made
OF closed, at high water, a temporary fall OF
rise is the effect. because then the river re-
quires some little time TO accommodate itself
to the sudden change in its requiem. 1t has
time while it is rising, if the outlet has been
closed or opened during q low stage. For the
thousandth time we have the river Pc COM
pared to the Mississippi. Levees were not
the cause of the rise in the bed of the Pc;
only the effect. The cause was and is the ec-
tension of its delta into the sea. The head
being constant: the extension of its delta for
Is or 80 miles into the sea, during a period of
1000 years, of course changed its plane of
descent and elevated the river between the
extremes, or head and discharge. In order to
retain the land already reclaimed, the leyees
had to keep pace with this rise but they were
not the, cause, only the effect. In the course
of the next thousand geaxs this may to some
little extent be the case with the Mississippi,
but assuredly outlets will not prevent it, or
retard il, unless we give up all to inundation
and go back 70 the primitive wilderness. In
every instance where the old or original levee
exists, and there are hundreds of such locali-
ties, it (the riyer) is no higher than at first,
IL III - q 81 -E% IL