The Cairo bulletin. [volume] (Cairo, Ill.) 1872-1878, 1877-11-04
IMPROVEMENT OF TIE MlSSiSSIP-
III RIVER.
CAPTAIN EADs BEFORE THE CINCINNATI
a MERCHANTS EXCHANGE.

CAPTAIN EAps BEFORE THE CINCINNATI
ono MERCHANTS EXCHANGE.
Cincinnati Gazette, Oct. aOlh.
The subject of the jetties at the mouth
of the Mississippi river is one which is a
matter of much criticism and some COM
mendation. Capt. James B. Eads arr-
we'd In this city last Sunday night, and
yesterday was present at the Merchants
4 Exchange, where he was invited by
president Hartwell to explain his views,
not only as to the jetties, but as to tie
| Improvement Of the Mississippi river.
The address, which was atten-
lively listened to by q portion Of the gen.
tlemen on the floor, was illustrated by
drawings on the blackboard, and by a
small map of the mouths OF the rivers.
Whatever may be thought of Captain
Eads' theories, or Of the success OF his
plans, it is certain that he supports them
with skill and energy. Abiding to the
jetties, he said that a depth Of twenty
and a halt feet had already been obtained
in the South Pass. He described the
methods of building the jetties, and the
works that had been constructed at the
openings where the main river was
divided into three separate chan
nels. Taking up the topic OF
the improvement Of the Mississippi, the
speaker explained that his plan was d.
rectly opposed to the one proposed by
the commission appointed In 1875 to re-
port upon this subject. The plan re.
ported to Congress contemplated the
completion of the levec system from
Cape GIrardcau, Missouri, to the mouth
Of the river, and the erection of leYees
along the tributaries as tar back as wa!
necessary to prevent overflow. 1t alst
comprised the retention Of Bayou Atch
afalays as the outlet for Red River
These works were estimated to cosI
about $40, 000,0 900. Capt. Eads set forth
his own plan thus:
In flood time, the Mississippi water
even at the surface and aboye its deepest
channels, Is found to be charged will
sand ant earthly matter. These are evil
IDENTIFY upheld in suspension by the cur
rent, tor il the water be kept at rest they
are deposited, and it becomes clear. Al
the current is the cause of upholding thl
matter. it follows that the quantity sus'
pended will be increased If the current b.
quickened. This increased quantit.
must be taken up from its bed. If tn
current be diminished, it Will sustain les
OF it in the water, and portion will tai
in the channel. Hence, If the current b.
made quick, an enlargement or deepen
ing OF the channel will occur. This i
called scour.
1.-THE current be made slow, the size G
, the channel win be reduced, or it will b
elevated by the sediment which falls int
1t. This is called deposit. The rive
can therefore elevate or deepen its owI
bed, according as its current become
too rapid or TOO slow. II it deepen it
bed where the current Is too rapid, tn
deepening must soon cease, because tn
surface slope Of the water, which produ
ces the current, is lowered, and the We
loclty diminishes as result OF the enlarge
ment or scour. In like manner, the dc
} post will finally cease, for, as the be,
! Is elevated or reduced i
size, the slope Is made sleeper and tn
current more rapid. We see, then, tina
the river can not only raise and lower it
, own bed by the action of the current, bu
that these two opposing agents. scou
and deposit, enable it to control Its cur
rent AMI keep 1t from running riot. W
will presently see the necessity for con
trolling this mighty current, which i
forever flowing oyer bed of its own de
posts, which 1t can again take up o
; throw down throughout the eleven hur
, dred miles Of its devious channel to tn
. sea, according to the needs of the river
Q The ability OF the current to suspen
0 the sediment Is modified by th
d. depth OF the stream, and il
. regularities In depth will, therefore, re
: quire the normal current to change wit
the depth also. The friction OF the wa
ter In flowing through the channel be
$ Is the chief obstacle to be overcome b
. the current In the effort OF the river [
. maintain the normal velocity. Gravity {
: the fall Of water from higher to lowe
} level Is the force employed to overcom
this and other retarding influences.
i The intensity OF this force is indicates
by the stcopness Of the slope or the fal
per mile OF the surface OF the river. Tn
slope In highest food time determine
the height OF the levees as they must b,
above II. We will, therefore, hereafter
refer In speaking Of slope to the hoot
: slope only.
r The friction Is least when the stream
ilows In q single compact mass, for ther
the surface of the bed In contact with wa
ter 10 minimum. II the volume he d.
2 Yided Into equal Oh annels by an island