The New Orleans Democrat., 1876-05-29

Eads and Mr.. q. w. t. Bayey. both Of whom
stand In the front rank of civil engineers. Ihey
concur In the opinion that crevasses form bars.
In hjs Physics and Hydraulics OF the Missis-
sippi River" Capt. Eads says: y
Uhe riverl scours out increased room for ltselt
whenever its current is accelerated, ana its de.
posits are sverEwhepe found where It's current sa
m rent Tia is checked by the depletion Of the river by
q creyasso deposition Of sediment will occur
below the crsvasse. because the slaekenlng oi
tho current caused by the channel below being
then too large for the diminished needs OF the
river would cause the water to deposit part ol
its sediment andshus raise the bottom o., o. the
the natural current was restored" We know.
again says this distinguished engineer. that
shoals are produced below crevasses.
and that they will disappear when the creVasses
are closed"
But Mr. Bayleys sounding conclusively prove
this theory to be true. In recent panphiet
published by him on tho subject OF Lovocs as q
means of recaming lowlands, he gives the re-
suit of his soundings Mt four points on the river
two above and two taken Just below the bonnot
Mr.. Bayley says: "On September 90 81 fafter
tho occurrence Of tho Bonnet Carre crevasse in
April lsi when The E river was yGry I nsaty ,saa y
measured and carefully sounded two river sec,
tions above the crsvasse outlet. one opposite ana
two below 1t, taking transit angles to each sounu
ing Sections one and two were taken one ana
one and three-quarier miles above inc ohtiet,
respectively: sections four md I'VE were taken
80 and 1000 feet below tne outlfI, SNflipiS Vne
and two taken above the creyasse) gnyo the FOL
lowing dimensions. respectively: WItths, low
water 2as6 and 3os feet. maximum depths 10
and 70 feet; mean depths 6t and 81 feet. sec
tonal ~ ens 1871 653 aud l6i 1G7 square fo"t high
water width 3i20 and 1910 feet SECTIONS four ana
five taken balow tho crevassel gave ne follow
ing dimensions, respectively: Nldths. low
water 2to6 feet and 24b6 foet maximum
depths 6l and Gi feet; mean dept,
20 and a. feet: sectional arens $3.50 and
Ioe 10 square feet high water width $500 aud $3.50
feet Thp average dimensions of the two upper
a nd the two lower sections were as follows: Low
water widths 1850 and 2429 leet: depths. 80 and
l G5 feet sectional area 17t ,i0 and lOl .95 teot
Reducti Of channel below average OF upper
and lower sections in width, at low ter 52l
tect; in depth. average OF whole sections OF ~ az ~
feet-sauare feet. Tho mean high water soc,
tional area above was 2320o3 square feot. and
ssEW 'Sss st Ths s'H" Ho"m o ofaw he %
bed whom the upper sections were taken. con
sisted Of flrm blue clay. into which the elevon
incnes only oil the way across; while the depths
we're tperably uniform all indicating channel
of full natural dimensions. free from deposits
The bottom, when both the lower sections were
taken was soft oozy mud or silt into which the
sounding lead sunk from one to two feet. except
near the left bank, herethe current was strong
est, on the bend side OF the river where the bot
tom was also firm clay and free from deposits.
Opposite the lower sections the sand bar on tho
right bank side had encroached upon the chan
ne 40 much that the low water width had been
reduced more than bOO feet. and new sandy
ridge. evidently q deposit made during. the
preceding high water from twelve TO fifteen
feet high at it's lower end had been formed
above the low water line and over the old bar, In
a direction para lei with tho thread OF tho cur
rent. from the river above into the outlet open,
ing Very extensive new deposits Of sand had
been mad, In tho right bank bend next below.
several feet high above low water. and extending
several hundred feet out from the shore line;
these were known to be new. Evorythi <. the
ne sand bars and sandy deposits. the new,
oozy mud or silly deposits. extending nearly
across the river channel below the outlet, and
the very great reduction of channel way below
caused thereby indicated most unmisiakably
that this Bonnet Carre crevasse outlet Of 1874 did
cause partial filling up Of the river y below
Xne cxper ments and Oh ervationS OF Mr. Bay
" leave no room to doubt the fact that the Gre
vasses of the Miss ssippi river swiftly and di-
retly operate the formation OF bars In the river
effect OF outlets upon Red kiver and especially
the outlet known az Tones Bayou, some twenty
miles below the city Of shreveport
In twenty five years this ba, ou. which. whom
cleared out. was an insignificant outlet has in
creased its sectional area to $500 foet while that
Of the main rivef od,oW y ina mas oecn fa.
feet and It's channel has been contracted some
800 feet. An official report confirms Mr.. Bayley's
statements and attributes the decrease In area,
w .dth and depth to the outlet above. which has
been" says the report. constantly enarging"
Mr.. Bayley includes that tho same law gov
great. The first effect OF an outlet is to lower
tho food line Of river, because time Is required
to adjust the rivers regimen; but the ulti-
mate effect the reverse, because the law IL that
the less the quantity of water flowing. the great
sr is tn, slope required for its discharge at a
given velocity.
doubt but tn It the ere asses Of the Mississippi
river are forming bars constantly and ot%lT
ing in q measure, the commerce OF the river.
and that il the theories upon which they base
their conclusions be true. tho outlets. II not
closed will deepen and widen, and the bars will
grow and the obstru tions become more and
tnty fhn p,f I'M ltl ,f
the great river will utter q cry for relief that
Congress will be obliged to heed.
But again: the commerce OF the mississippi
has suffered and is suffering all the time. bo-
cause of tho crevasses and tho unsafe con
d,tion of the lovees that still stand. The
creyasscs, some OF wi, which d are nail a mil, mll'
wherr they leave the river channel. crcats
atremendous suck from the very centre Of the
river Into this maelstrom flatboa,s. rafts.
barges and trading boats are constantly drawn
and destroyed. The powerful steamer. in day
Tune passes them in safety at night, however
and when the weather Is not clear land dense
fogs are Of frequent occurrence on the Missis-
sippi riyerl. the steamer il obliged to tie up and
wait for daylight or the lifting of the fog TO pass
loat and others have been damaged by being
sucked into these dangerous outlets. The
steamer Katie. one Of the largest and finest
tho vortex of Bonnet Carre within a few woeks
past. and with her. hundreds Of lives and 1000
bales of cotton came near being lost. She saved
only pulled from her peril by tugs sent from
New Orleans for that purpose. Other instances
are well known Of the toLal loss and destruction
Of steamboats, in this way.
But again the trans portation and delivery of
freight mails and passengers is constantly re-
tarded and hindered in food season for lack Of
safe levees. When the angry volume Of waters
has risen 10 a level with the frail embankment,
steamers, for many miles, cannot land for fear
Of breaking the levee. or that the waves made by
their motion may wash over and dissolve them.
Hence they are obliged to carry freight and pas
sengers miles away to some safer point. and
land them very far from their destination. To
the superficial observer the danger to levoe
from WIVES created by passing steamer might
sem frivolous. But the exact force and might
Of these waves. induced by the motion Of the
steamboat, nave been measured and ascertained.
We quote now from report OF the special com
mittee on the Mississippi leveos. made BY the
Fory-Third Congress-, and prepared by Dir.
Morey now member Of this committee:
The claim of the inhabitants Of the delta for
national aid rests upon much stronger grounds
than mere prospec, i've revenues and produc-
tions These claims come in tbs form of recIa-
nation. They are based upon the perpetual
and ever-increasing attack upon the levees by
the passing commerce OF twenty-six States and
Territories of the Union. The steam
prs that trapapOrt this commerce send their