Memphis daily appeal. [volume] (Memphis, Tenn.) 1847-1886, 1882-03-08
CAPTAIN EADS On MIsSISSIPPI M.
PEOsEHEN

II mas been an old saying among river men
that the Mississippi river presents a Phenom-
enon so peculiar that there Is no accounting
for its movements; like woman, "when she
will she will, you may depend ont, and
when she won't she won's, and there's the
end ont. When, however, Captain Eads
stood up in the Memphis Theater, and in his
simple, unadorned way explained to his
audience the various phenomena Of the river,
and reduced its apparently muIiform
changes to the operation of very few sim
pie clements, and showed how by awaiting
ourselves of that knowledge we can control
the flow of the stream, deepen its channel,
and clear away its bars and shoals, and pro-
vide against destructive foods-it was felt
that there existed one man who had read the
mysteries of the sphynx Of the waters, ard
knew the spell by which its vagaries could
be mastered. That explanation was last
week repeated by him before the House con
gressional committee, and the secret Of the
hydraulics of the Mississippi laid bare where
their unfolding "would do the most good"
Captain Eads's knowledge is the result Of
study, founded upon extensive investigation
The whole length of the stream used for
ordinary navigation has been subjected TO
his minute investigation. Not only the banks,
the soil, the rock and the outlines of the
shores, but, descending in diving bells,
he has personally examined every part Of the
bed of the Mississippi itself, so as to spy oui
and understand what had hitherto been hid
den from mortal knowledge. His thorough
acquaintance with the subject, and his clear
and obvious conclusions drawn from the facts
he detailed, won for him the most profound
attention on the part Of the committee. With
vivid clearness he instructed them in the
science of the subject, and made them com
prehend that the waters of the Mississippi,
from the mouth of the Missouri down, carry
an unusual amount of water in suspension;
that that amount varies as the rapidly Of
the current varies. Where the banks APP
proaeh nearer from opposite sides the stream
flows more rapidly. So flowing, it takes up
and carries off a larger than average amount
Of sediment. When the banks retreat, or are
low, so as to allow the water to spread lat
orally, the stream, as necessary conse-
quence, moves slowly and in proportion to
the width. As the motion Of the current de-
creases its power to carry suspended matter
decreases, therefore portion OF the sediment
gathered in the narrowest parts fall to the
bottom and form the shoals and bars that
obstruet navigation and promote overflow at
high water. Here are the simple but Ell
Gent causes, now what is the remedy
knowledge OF them suggests? The rem
edy lies in an equable current, as such
a current will carry an equable amount Of
suspended sediment, no longer taking it up
where the motion is rapid to deposit when
it is slight. The rapidity of the current de-
pending upon the width of the stream, rapid
in the narrower and slow in the
ly lies in making the width of the
stream approximately equal in proportion
to the distance above the mouth. This
approximation can be made, sufficient for
practical purposes, by constructing artificial
banks, like those at the jetties, where re-
quired, and so preventing high water from
overlooking neighboring lands, while the
quicker current thus acquired would wash GU,
the shoals and clear away the bars. These !
artificial banks, by emitting off the mischievous
widespreading of the waters, would-taking |
in the whole extent of the river-reduce the |
average rspidity OF the flow. This increased |
rapidly would wear away to greater depth
the bed of the river and on the principle |
that a larger pipe will carry off more water |
than a smaller one, the increased depth would |
carry off the superabundance of water when |
a rise came and thus reduce the liability |
to damaging floods. Those who under |
stand the very simPiv principles here |
laid down cannot fail to see the fall |
lacy of the cutoff system. Where a cut |
was made and the stream allowed to dis |
charge portion OF its water from one side, |
the amount OF water being reduced, the pres
sure which determines the rate of flow would |
be reduced. The flow being more gentle,
could not carry as much water in suspension
as before-other things being equal-and
shoal or bar would be farmed in conseq uence.
The true system is to coufine the water in
its channel, then it will scour out its bed TO
a greater depth, and in so doing give relief
from destructive floods and secure an even
depth of water for navigation unobstructed
by bars and shoals And this remedy is one
equally as advantageous in low as in high
water, for the depth and regularity of the
channel would always allow of navigation.
In the desire to get rid of excessive high
water, this necessary provision against ex-
,essive low water is sometimes lost sight Of.