The daily crescent. [volume] ([New Orleans, La.]) 1848-1851, 1850-06-03
The mississippi valley and River.

Vhe m1Ss1ss1ppt valley and River
Upon Cutoffs and Artificial Outlets-
To the Editors Of The INep Orleans Crescent:
GENTLEMEN: The mischefs arising from Cut-ofs the
artificial strengthening Of the natural bends of the Ms
sDpi generally known and admitted, all bands it is
scarcely requisite that should point to this enlightened
community the causes whence such evils result; but,
in the discussion OF subject of such importance to the c
of Louisiana, that which have taken up, shall
briefly alude to the primary cause - whence such dis
astrous &C effects - arise.
In a preceding letter of this SERIES (No 40 remarked
upon the nuosty of the Mississippi and the effect which the
" bend" maintained the velocity of the current and
referred to their acting dams todve back the of
the river. Upon this subject Professor Dnesbsch, of Erie
burg writes bends in rivers incomplete rivers dam
back the water and produce swell above the river-an
walton of the waters suraceaud therefore decrease of the
velocity Thus then, the tortuous Of the Mississippi
mecfu dispensaton Of Natures laws bywhich mankind
benefited The dwee upon the banks Of this truly
dous river have the distance ofver carriage heightened
by this provision. and portions of the country through which
the Mississippi in its stupendous meandeDgs flows, have
through its medium, vehicle by of which their pro-
duee and manufacture be easily and economically
ported suitable market; while the other hand, had
the rivers course been straight than nehaf the water
privilege, available, would have been lost besides
the unresrained Impeuosy Of the would have
tany impeded, if rendered the navigation mpraccabe
altogether; and auredy the State of Louisiana and all the
district of the Lower Mississippi would have been
flowed by the spreading waters to have rendered these
bends unavailable for agricultural commercial purposes
to be apprehended from cuof. For the clear eucida
ton of this matter shall premise that the acceerang
for the motion of running water currents in rivers the
inclination grade of their BEDS and the specific gravity of
the component parts Of which the fluid is composed The
retardng the OF rivers, and tending lessen
their volume in cubcal contents are evaporation, entera-
on hrough the bottom and banks) capillary attraction,
cohesion of the component particles friction against the banks
and bed and sepentne windngs 10 the MYERS course Let
suppose, therefore, that there bend in the Mississippi
of sixty miles length, and that the fall in that distance
thirty feet decvity of six inches mile that by cut
ting through shmus neck of land, ten miles in
width the of the river could be shortened hty miles
what would be the effect? Certainly that the same column
of water which heretofore passed through channel sixty
miles in length and courng superficial surface Of Is, ,2O
acres Containing column of wuter of 900 cubic
yards should be then elected through passage miles
long with fall of three feet per mile, (for the maximum
fall would be idenuca,) otherwise, thus channel ten
miles long, with declnaton of three feet per mile, and
superficial content Of 300 capable OF containing only
g. 3 2100 cubic yards would have to dispose OF COL
un of heretofore contained in the large channel al
ready described where the current four miles per hour in
the sixty mile course while it would be accelerated in the
shorter beyond the power of (eertdiH) calculation.
This nco roverbe reasoning therefore manesty prove
that the weight and impeuosty Of any volume of water
thus prematurely preepitaed through cutoff against tn
next concave bend below the artificial saightening mus
cause much greater abrasion of the banks heaping up
the that point from the resistance Of the unaC
cerated movement of the waters in the next section of tn
discharge the unnatural accumulation of water and therefor
an inevitable nundaton of the country. and giving way
the evee or at some concave beBd where the
bankment weakest. The beneficial effects of cutofs
questionable in any yet under peculiar ecum
stances they might possibly be productive of good results
viz where batture has been under of formation 70
long of years. and where bends the
of great injury the opposing concave bank, when he
are commenced at the mouth of river. and systematically
carried upwards towards its source.
now come consider the evils likely to result to the navi
cation of the Mississippi and the inability of artificial outlet
or hydraulic safeyvaves for the distribution of the floods
this great river must again remind readers tha
one great and peculiarly, almost exclusively belong
ing the Mississippi is the large proportion of sediment
carries solution it known and admitted trusm, that th
specific gravity of such foreign matters induces precpita
ton or settling down to the rivers bed different Intervals
the time Of settlement being determined by the
tona ratio of the specific weight Of he particles, and the
time and distance required by the power OF gravation
overcome the suspensng influence Of the fluid, and the
iece force Of the current These conflicting forces being
overcome it selfevdent that sedmentaon Immediately
takes place Now the effect of artificial outlets will be to e
off the surface of the river at flood tne-that having
the greatest velocity generally the heavier annG OF thu
fluid lie the bottom, and Of course as the current
decreased in velocity the settlement OF the muddy particles
even timbe in the formation of basis sand banks etc.,
in the rivers channel. plainly most be prepdca to naviga
ton, but this is not all.
tcannot be denied but that the velocity the current
the ortuous nature of this rivers (Which occasion
des and counter curens) prevents the deposition of it
sediment as quickly would be the the curren
less impetuous the more rghtlned; but below
New Orleans where the river comparatively raghter ant
the inclination of its bed horizontal it approache
the Baze the velocity of the current retarded by art
cia outlets sand banks and Islands will spring up, if b.
magic at the entrance ofthe Mpp its bars will becom
shmuses, its mouths will be choked the river in shor
space will rum its mighty depths will form chain
| stagnantwaer holes, and New Orleans, the "Cescen
City, the pride of the South he wonder of the nations,
will be place for fishermen to spread their nets upon
modern Tyre and Sidon The evil effects Of artfeis
outlet from the Mississippi to Lake Pontcharrain at tn
Bonnet Cane bend is another and most valid objection to tn
adoption that system of (most questionable relief from tn
floods Observation has proved beyond doubt, that since tn
break the Bonnet Care Levee the lake has risen consider
bly, above the level at this season. The most sceptc
will be convinced of the effect the waters of the Mississippi
escaping at the Bonnet Care bend exercise upon the
ance of the color of the of the Lake and the d
rent degree in which they were impregnaea with salt befor
the cause referred to had taken place. 1t is also well know
TO the intelligent citizens of New Orleans that heretofore,
times under the influence of particular Winds the waters
Pontchartran have been backed up 10 submerse tn
swamp lands the Of this city, and indeed to nundat
the shell road and part of Canal street. What dsastrou
effects therefore, may not anticipate will result tor
making this lake the reservoir for the hoOdw OF the Mis-
sissippi, and receptacle forts sediment
regret that cannot argue with Professor Riddel who's
ingenious calculations tend prove that the ancla quite
at Bonnet Cae would not njuonsy eiect Lake fohtci
artran scubica for upwards oil one uousanu years
c, , benscia reults TO the navigation OF the lake wou
be the consequence and that "a creation OF arabic held
the upper part of the lake would ensue This quote iro
the Professors remarks upon the dynamics OF the Mspp
recently published. Also in the same ueatlse Doctor K'
dell states referring to the Hydraulic Safety Valve, at Boz
net Care cit would tend to deepen the bars which no
obsruct the entrances from the Gulf of Mexico into LaE
Pontebarrain The force of this reasoning am cOnstrane
N dissent from; because suppose part OF the waters OF
issppi 10 enter the lake through the proposed artifci
outlet nj Bonnet Care the waters would Immediately
over 3 square acres (he superficial surface OF the ak
The current would be comparatively lost when distribute
over such an area Doubtless it would be urged, in suppO
of athe position' that when the Mississippi discharges
ouanity of water into the lake, il must find egess into
open gulf the channels chef neRter and the rgOtt
Ians,er certainly portion must but evaporation and
sortion will dispose of large portion (where such wi
superficial exposed to their intuence) much great
portion than the like could effect if the waters we
confined in a narrower channel, such the of
Mississippi And again, the opposing force of the waters
the Gulf (explaned in No. of this SERIES where prov
that when the concentrated velocity of the current was
creased the greater specific gravity of the collision of sal
water drives back before the water less impregnaed vi
saline PARTICLES and prevents its egress into the Gun fl
acts as hydraulic DAM if may be permitted the expre,
Thus then contend that the artificial outlet scheme wo
innre the of both the river and the lake. and
tnae in closing upthe to the lake, and shortly,
month ofthe river.
Besides prepared toprOye that the artificial outlets