Sacramento daily record-union. [volume] (Sacramento [Calif.]) 1875-1891, 1884-02-25

reir .forcement by .evees is the more imper-
. lively necessary. To build levees, there
fore, is really to aid the river to deepen It's
channel, and consequently to strengthen
the leyees themselves, In other words,
levee.building is but to finish the rivers
unfinished work, and in the case OF the
Sacramento it is more-it IS to give spe-
cifc to an ailing river.
If the energy of river makes its chan
mel, any access of that energy will tend
that much to deepen channel or restore
its original condition. So, then, any dim.
mutton of the energy will tend to augment
the ailment and final destruction of the
channel. Energy is augmented by increase
of volume and depth, for volume adds to
the velocity, and the result is deeper and
better channel. Whatever, therefore, re-
duces that velocity, to just that extent
impairs the river, because it lessons its
energy.
Artificial causes to large extent have in.
jured the Mississippi as well as the Sacra-
mento, and artificial remedies must be az
Piled in consequence. Some very interest
ing facts are recited by Mr.. Taylor to
show the damaging influence upon the
river of unrestrained overflow, for overflow
or unnatural emission through the banks
tends &c produce diminished and irregular
velocity in the main channel, and of
! course stimulates the filling of it with sedi-
ment. Such emission and overflow give
local variations of velocity and direction in
the main channel.
Thus, in one part of the river the escape
may be great, in another small, few miles
distant, and these irregular discharges will
produce corresponding fluctuations in the
velocity and direction of the current, and
consequent retardation of flow and deposits
of sediment. Now, says Mr.. Taylor, and
here he describes the case of the Sacra-
mento river precisely, can overflow
through series of crevasses located not
far distant from each other, is substantially
| like an overflow across the natural bank.
The chief difference is that in the former
case the sections of discharge are more
sharply defined than in the latter, where
there is likely to be thin sheet running
over a considerable portion of the entire
front, with large discharges at bayous or
depressions in the surface"
In the flood of 1852 four crevasses on
the Yazoo front within a space of eighty
miles showed, by survey, filling up in
every case of from four to twenty.four per
cent. of the entire channel space. But if
the same amount of water had gone oUer
the levees on a longer bank front, the i'm
pairment would not have been 30 great at
any one place or SO easy to ascertain and
measure.
At Clayton, Ia, the overflow begins at
fourteen feet, and from that up to eighteen
feet the river in 1881 gained nothing in We.
locity. So at Grafton, ILL.,, as the overflow
increased the velocity ceased to increase,
and at last actually decreased. So in Mis-.
souri,, in 1881, for five hundred miles the
river covered the valley from bluff to bluff,
with nothing to retard its progress yet
its velocity so slackened as it rose above
its banks, and its rise SO increased as its
velocity slackened, that at st. Charles it
reached hight of three feet above that at
Sioux City, whereas the normal course of
flood is to diminish in hight above the
low-watsr plane as it flows downward.
We may not now pursue the subject fur.
ther, but the moral pointed is made already
sufficiently clear, and cannot be gain
sayed. Rivers, to be reformed or pre-
served, must be leveed in, all breaks
and artificial emissions closed, unnatural
emissions prevented, and thus the full
securing and bank. building capacity pre-.
served, and this not only for the benefit of
the river but equally for the safety of lands
adjacent thereto, although this latter is an
incident, and is never, we hold, to be made
an object Of the Government work.