The Greenville times. [volume] (Greenville, Miss.) 1868-1917, 1882-10-07

the MlsslsSlppl above NlckSburg
aa though the great river were
land. No levees built by man
could have withstood the power
of that torrent. Yet, had the wa
tiers been controlled above, and
kept out of the st. Francis Basin
and also out of the YazO0 Basin,
the levees opposite Vieksburg
could easily have withstoOd the
waters of the Yazoo. Subjected
to one adequate and satisfactory
plan, these forces are severally
controlled with an expenditure but
moderate compared with the value
of the end to be attained. Below
the mouth of Red River these dis
turbing forces are largely subdued,
as the river is straighter and deep
er there, and there are no tribu.
taries to disturb the levees, while
the resources of the State have
been expended to maintain them.
Moreover, the river here is reliev
ed from inundation by the fact that
the outlet through the mouth of
Red River and the Atehafalaya
takes all the surplus waters to the
Gulf. Hence the apparent com.
parative success of the levees be.
low Red River, while those above
have been generally abandoned in
despair by the chief interests and
authorities whose resources have
heretofore been expended on them.
1t is sometimes objected that no
system can force into one channel
such vast volumes as submerged
the Mississippi Valley last spring.
On the contrary the greatest vol
ume poured into the Mississippi at
its highest food is necessary and
useful to scour the channel and
sink the bed. Such objectors do
not appreciate the depth of.the al
luvial deposit over which the river
flows, and consequently the power
of the river to scour its channel
and deepen it's bed. The Missis.
sippi, below Red River, is but little
wider than ii is above Cairo, tho
carrying about double the volume
of water. BY confinement to one
channel, by long and well pre-.
served levees, it has Strengthened
and deepcned its bed. There can
be no doubt that by an efficient
system of levces, above Red River,
confning its waters to the present
general course Of the river, it will
scour it's bed down to any depth
requisite to make room for its
greatest accumulation of waters
without wideningits surface. Such
Increase IN depth would of course
be accompanied by decrease in
fall, which would tend to slacken
the current and so make the river
shallower by deposit of sediment
in its bed; but on the other hand,
this tendency would find q correc.
tive in the increased momentum
which, when the water is high,
would tend to cut off the bends,
take the kinks out of the river, and
shorten its line, thus restoring the
fall per mile and consequently the
speed of the current and its power
to carry its sediment to the Gulf.
The volume of water when floods
cover the valley is not so much
greater than at times of ordinary
high water as is commonly sup
posed. The great basins ! have
described become reservoirs rath-
er than channels, and, though low
er than tho Mississippi, the resis-
tance of the surface to the flow of
water over it is so great as to
check and still the current, except
at the localities of reception and
discharge.
To this overflow, through these
great basins, is to be chiefly at.
tributed the increased difficulties
of navigation from Stacking the ve-
locity of the main current, and
consequent filling up of the chan
mel with a deposit of the coarser
sediment. To explain the manner
of compelling the river to change
this process of building up its bed,
to the great injury of navigation
as well as the danger of its forsak.
ing the present channel, we will
commence at the mouth of Red
River and proceed up the Missis.
sippi. From Red River to the
head of the Valley the Mississippi
has a slope of about 255 feet, run.
ming over an uneven bed, giving a