The Cairo bulletin. [volume] (Cairo, Ill.) 1872-1878, 1877-11-10

appropriation, ia the ordinary way, NJ 50
much annually out Of the pubic revenues
would answer the purpose. The con-
strucliOn OF the leyees Is without doubt
demanded by the true interests OF the Mis-
slppi valley, and II Is only question 81
time when IL will! BE- brought about. The
immense tracts Of richly productive land
to be reclaimed offer u prospective yield
that Will amply repay the cost OF lcvees
and add greatly to the reno wn and wealth
Of the country. fs gL4ft
There il, by the way, quite u remarka.
HE difference ot opinion among leading
engineers as to the most practicable mode
OF preventing the disastrous ovarflOws
which have retarded the development OF
the valuable bottoms along the hlississip>
pi. The Commission authorized by Con.
gress Ia lS74, Of which General Warren
was President. unanimously agreed that
division OF the water flow into various
channels would lessen the depth Of water
generally and prevent lis rise SO much
above The natural banks. Hence the
commission recommended that outlets
be provided by sipe channels, which
would assist In carrying OIL the
Hood. 1t was claimed that high levees,
combining the river into comparatively
narrow bounds, would necessarily occa-
sion q greater rise and that nundations
would still result unless the artificial
banks were raised to a great height. This
plausible theory, however, does not meet
with universal favor. Capt. Eads takes
contrary view OF the matter and asserts
that the result OF cOniining the current
and limiting its width, would be the &c.
curing of a uniform channel, and the pre-
ventiOn of deposits raising the river bed
and the liability to 0verflows. "By mp
plying the principles laid down in the
theory of Captain Eads at the beginning,
it will be seen that the wide, lake-like
places In the river are the cause OF nearly
all the troubles which beset both naviga-
ton and agriculture throughout the ais
luvlal basin. When flood occurs the cur
rent Is very rapid in the narrow places,
anil consequently highly charged with
sediment. In the wide places it is slug
gish, hence deposit takes place extensively
in the latter and great shoals result,
which are infested with snags. The
water, after passing out of these wide pla-
ces, deprived OF part of its burden, in
creases its speed and loads up again from
the bed and banks Of the next narrow
part, and carries the spells taken here to
the next wide place. This creates the
cavinS banks, the cut OAs and rapid chan
gcs In the stream. The shoals are simply
efforts Of the river to build up the bed
produce sleeper slope to restore the nor
nal current velocity.
BY a uniform width Of the river banks,
a uniform depth would be secured this
would produce uniformity OF current
and prevent the caving Of banks, and it
would lower the tlOOd.slOpc below the
surface OF the land, because 1t would re-
move the excessive fractional resistance
created by the wide river bed. 1t only
needs the ne.tifth part OF an inch per
mile of reduction of slope from Cairo to
Red river to lower the Hoods l2i feet at
Cairo.
The narrow parts OF the river below
Cairo seldom have less depth than thir-
ty feet in low water in them, and Capt.
Eads is confident that reducing the river
to uniformity of width would give a
uniform depth from Cairo to the sea, dur
ing the lowest water, of at least twenty
feet. No Strengthening OF the river is re-
commended by him." The subject is
one of such vast Importance that it de-
mands the most careful investigation,
and before the adoption of either plan its
feasibility should be proved by deliber-
ate experimental tests.