The New Orleans crescent., 1868-03-29

The season OF high water in the Mississipp pi Is
unfortunate for the planting interest. In the Nile
the overflow ceases before 1t Is necessary to put
the crop in the er6und. In our great river the
planting preced es The flood; and hence that which,
10 the case Of the Nile is regarded as the greatest
blessings, on the Mississippi is dreaded in de-
gree winch only those who have Witnessed gen
Such are. in few words, the physical character
istcs Of the Mississippi river. The normal effect
exerted by its sea Of waters upon the lowIands is
next TO be considered. Their general shape and
extent have been already indicated, as well as
the fact that the surface soil throughout Is mostly
composed of Mississippi alluvion. The average
depth OF this a'uvion 10, however. smsll-not ex-
ceeding twenty five feet The real bottom of the
river underlying its moving sand bars-belonqs
from the mouth Of the Ohio 70 the gulf. to geo
| logical formation older and composed Of more te-
nacions materials than the present. This fact has
controlling influence upon the general stability
| Oh Ihe chsDnel. There is no evidence to show
| and no reason for believing that it ever in our
| epoch differed materially from its present loca-
ton. Among many facts which confirm this view
| rs that of the general slopes along the lowlands
| They fall from. north to south ct an average Of
about eight inches to the mile; while at tight an
| giles to this direction they slope away from the
| river at sn average rate of six inches to the mile
The immediate banks of the river are thus several
feet above the land bordering the bluffs, and water
| escaping into the lowlands flows away from the
parent stream in sontherly direction until il en-
high to turn it back many miles south OF its point
or starting. The ST. Francis and Yazoo rivers are
largely made up OF such streams, whose channels
also AFFORD drainage to the immediate downfall
upon the lowlands, while the bsyous Afchafa-
lays and Lafourche, encountering no ridges in
tnelr courses, flow by separate channels to the
Gulf. This general slope of the land away from
the main stream is highly characteristic Of sedi-
menl-bearing rivers, liable to overflow their banks
The heavier and more bulky particles in suspen.
sion are naturally deposited first. when the veloc-
ity is checked, and the immediate bank is thus
raised. On the Mississippi river the average fall
from the river In the first ile is about seven feet
at greater distances the slope is, OF course. much
less. III i had undergone any extensive change
OF enamel In cur epoch, the general slope of Its
lowlands must necessarily have made the fact
known. /
Because the general permanency of the bed OF
the Mississippi is remarkable, considering the i'm,
mense volume and velocity of its foods, it must
not be inferred that local changes of an important
character are not occurring. Below Baton Rouge
the regimen Of the river has been comparatiyeiy
fixed, but above that point it is constantly under.
mlsing and washing away land IN the bends only
10 deposit upon the points. After time the re-
suit OF this action would be to 80 reduce the slope
and hence the velocity of the current, as to in
duce some stability OF bands; but, unfortunately
the course of the river is so serpentine that the
wearing away of two opposite bends often results
in uniting them; thus leaving first an island, and
ultimately by the silring up Of the ends of the old
length
i thus reduced, il may be twenty miles, and the
efors to lengthen its channel is again stimulated
10 new activity by the consequent increased We
locty OF the current. CayiDg of the banks II
therefore, in the upper river, the chief obstacle
IN reclaiming the country from overflow.
To rescue this garden of the New World from
the dominion of the Mississippi was the great pro-
6lem presented to civilization when, in l7I7. De
La Tour laid out the city of New Orleans The
system then adopted by that eEglneer has been
followed, without deviation, mp TO the present
tme-if We except few ill-judged attempts az
making cut offs IN the present century. Governor
Perrier, in l727 announced the completion of the
New orleans leyee-a tiifiing embsnkment about |
mile long. In the following year we find there |
were five colonies extending thirty miles above |
New Orleans, and obliged to construct leyees Of /
earth for their protection The system was TINS |
fairly inaugursted- AT this early period no great
height was required for the entertainments. as their
limited extent left ready access TO the swamps In
places where back water would iDiure no one /
but as early as 1875 1t recorded that the nod
caused the levee to break in many places.u For /
.ixty or seventy years the levees were but little |
extended, owing to the wars between England |
md France, and the cession by the latter power |
y her colony to Spain. who ruled it badly In |
800 the territory was ceded back to France and
= lovS 70 the United states. Then beganits rapid
growth, as indicated by the extension Of the eyees
10 and down the river. 10 1850 they were COM
lleted nearly continuously from a point fifty or
lxty miles below New Orleans TO the mouth of
be Arkansas en- the west bank, and 10 Baton
Rouge on the east bank, with many isolated
evees along the lower Yazoo front. The
versge height Of those levees was some.
Vhat less than five feet, or lust sufficient
o restrain the usual spring floods. When.
M yer grea. food" occurred the country
vas inundated, and great suffering was entsiled
pon the entire community. The enormous pro-
re OF the culture Of cotton and sugar enabled the
anters, even with this drawback, to repair the
avees, TO literally provide for the negroes, and
ountry from the mouth of the Ohio to latitude 35
egrees 80 minutes was best adapted TO the enl.
ure Of corn; thence to the mouth of Red River
latitude 81 degrees, to that of cotton: thence
. the gull, to that of sugar. The northern half
TINS region was almost wilderness in the Low
lnds. |
The year 1850 was noted one 10 the history Of
lis region. The general government then dona.
"a 10 tne several States the overfowed lands |
lfhln their limits to provide fund for reclaim |
e them from the river. The State of Mississippi
lus received about seven Thousand SQUARE miles |
le state Of Arkansas about four thousand souare
lies, the State of Missouri about three thousand
iuare miles and the States of Tennessee ,
I'D Kentucky less extensive tracts
bus stimulated, the work of reclaimng
le alinvial lands above Red River was entered !
pom ia earnest; and by State legislation its ulti
ate completion was placed beyond a doubt '
Ihis action alarmed the planters Of Louisiana | /
ho reasoned that the closing of the immense | !
servors furnished by these l0wlands TO the Mis-. :
sslppi Hoods wonld result in greatly increasing 4
eir height in Louisiana, and would thus render
much greater height necessary for the leyees 4
indeed, II did not render this system of nro.i 6
ctlon entirely nugat0Ty for that State. This nm v
reseen result OF its legislation being brought 20
e attention OF Congress, that body made a large =
preparation, which was duly approved by the \
esldent. for causing the necessary surveys and \
vesugations to be made to determine the most !,
acucabie manner of protecting the country n
alnst inunoation. This subject was placed IN p
arge or Major General A. A. Humphrevs-tben n
pain and now chief of engineers, United states "
my. His operations extended through ten n
aIs; and their results were published lust after n
{ beginning OF hostties in 1861. The figures
THIS al lucle are taken from that report. which
IS full and elaborate.
The different plans of protection somet;mas y,
alsbie in similar cases for lesser streams~ =
nely, diveriing tributaries, holding back bv Y
liiclal reservoirs the surplus food Of water ~
used IN improving low-water navigation. in. re
Easing the velocity. and thus reducing the Hood sc
ght by cutting of henes makinc ne " outlets 70 q
sea--all proved inapplieable TO the problem &C
ssented by the Mississippi. Il was, however OF
o"n that the reservoir actions of the great eT
amp basins OF the upper river ia moderating b
Dos hso been overestimated; indeed that while 70
ressing the difficulty Of reclsimng that district IA
y hardly affected the problem in Louisiana. and So
y the levee system, properly carried out offered
ure protection TO the entire valley. at fnt1re re
lay OF ahout seventeen millions of dollars. &