Sacramento daily record-union. [volume] (Sacramento [Calif.]) 1875-1891, 1882-03-29
THE PREVENTION OF 1suspATloNs.


methods of protection hitherto adopted
to be called in question. Indeed there is
growing disposition to condemn the
levee system as having broken down. This
verdict, however, cannot stand, for though
the Mississippi levees have given way tins
year, it cannot be forgotten that they
have proved eminently serviceable Tor
many preceding years, nor must 1t De
ignored that no known system can De
devised which will give absolute guaran-
tees against similar disasters. 1t is no
doubt easily explicable that the injured
communities should in the first burst OF
disappointment and dependency denounce
the levee system as a complete failure,
Init before the United States Government
decides to give up that system it will re-
ouire proof of the possibility of improving
the river defenses of the Mississippi val
| lev, The Nile and the Pc have long been
the favorite models for embankment en-
gineering, but the weakness Of all
attempts to infer from the treat
ment of these rivers the course to
be followed elsewhere, consists in the fact
that the circumstances are not alike. The
| Pc and the Nile have been treated with
single eye to the local requirements, and
that is the only rational mode of proceed
ing in such cases. Because longitudinal
or lateral dykes, or broad or narrow en-
bankments, suit an Italian or Egyptian
locality, it does not follow that they
will suit an American river system. Au-
thors like Lombardini, therefore, while
they can give us ample information as to
their specialties, must not be followed
in an abjectly initiative way. In fact no
theorizing on these matters is of much
value.
In determining the best mode of treating
a river it is necessary to ascertain the
sources of its supply, the distribution and
character and amount of the rainfall, the
topography of its watershed, the capacity
of its outlet or outlets, the direction and
gradients of its channel, the character of
the soil through which it flows, the extent
and nature and value of the agricultural
or other interests threatened by inunda-
ton, and several other matters which can
only be learned by patient local research.
Thus it might make radical difference to
the engineering treatment of river
whether its bottom lands were closely cul-
tivated or not. Take the Mississippi as
case in point. 1t has been suggested since
the recent floods that it would be better
to separate the embankments more wide
ly; but this would involve the sacrifice of
vast areas Of valuable property, since it
would necessitate building the levees be-
hind many of the plantations, instead of
in front of them. 1t is clear that this
sacrifice of property might be so great as
to negative a treatment otherwise desir-
able. In the same way it is impossible to
consider the question of rivers affluents
without also considering its outlets. For
it may be doubtful whether it will Be bet
ter to treat it for foundations by checking
the rapidity of its atfiuents, or by enlarg-
ing the capacity Of its outlets, or by both
methods.
The Mississippi valley has been examined
by competent engineers with view to
determine these questions, however,
though many of those who are now dis
cussing the levee problem appear to have
entirely forgotten the investigation of
Humphreys and Abbott. The report of
these gentlemen on the Mississippi con-
stitutes the most valuable compendium
of trustworthy information on the subject
at present extant, and it is significant
that they declare the longitudinal sys.
tenn of dykes to be the only ones
susceptible of advantageous applica-
ton to the Mississippi. This opinion
is no doubt logical inference drawn from
scientific examination of the situation,
and it must carry more weight with it
than the present clamor, even though the
latter may seem to be supported by the
failure of the levees during the recent
floods. We suppose it may be taken for
granted that no preventive measures can
secure absolute safety against floods to the
Inhabitants of river bottoms anywhere, and
this because it is always possible for an
amount of rain to fall at the headwaters
of river in excess of the capacity of the
channel to carry away without OVERLOOKING
the banks. There are, however, means
by which in given circumstances the flow
of rain into rivers may be checked, and
other means by which their discharge
capacity may be increased.
The Mississippi drains go enormous
watershed that it must always be difficult to
control its food-waters by any methods.
The levee system, however, has been at
lelst as successful as there is reason to ex-
pect any system could be, and even if the
capacity of the outlets Of the river could
be greatly enlarged it would still be impos-
sible to prevent foods, nor would the
change effect much relief unless the
velocity of the stream could also be so in
creased as to make the passage of much
larger volume of water possible II the
velocity of the current cannot be heightened,
the only effect of widening the levees
would be to check thecurrent still more, and
thus to decrease the power of the river to
carry off its food volume. By a system of
lateral levees the destructive force of the
floods might, perhaps, be diminished con.
siderably; but such system would also
tend TO retard the efilux of the inundation,
and consequently would interfere very
seriously with the cultivation of the
overhowed lands. The damage done
by such a foOd as that of the
present spring is certainly very great, and
it is not TO be wondered at that the suffer-
ers should cry out for some more trust.
worthy form of protection. But there is
no evidence in history that man has ever
yet succeeded in completely bridling such
| a river as the Mississiuui and TIE moro