Tensas gazette. [volume] (St. Joseph, La.) 1886-current, 1913-12-05

level country, where low dams cal
form lakes Of large area, IT may b
practical to control floods by mean
Iof reservoirs. There is hut a com
/ paratively small section of the Mis-
sissippi basin that fulfils either o
these conditions, and in such area
the rainfall is generally light. Tn,
rolling country which forms tn,
greatest part of the Mississippi valley
and from which the water that pro
duceS its floods is derived can h
protected from floods by reservoir,
only by IN enormous expenditure
Cut -OhS-By cutting off the bend:
I in river its length is diminished
and slope increased This would in
crease its discharge NJ given height.
This method Of relief cannot be ap-
piled to the Mississippi river, as
lit would seriously injure its nav
liability during low water and
increase the caving of its banks,
which is now excessive. While it
would afford relief in the upper por-
tions of the section of the river thus
Strengthened, it would increase flood
heights Mt the lower end, benefting
one locality at the expense of another
Outlets-Outlets. while locally re-
ducing food heights, have only
limited application as means of
relief from Mississippi floods. They
can not be constructed above the
mouth of the Red river; their in
fHence on flood heights extends
only a comparatively short distance
above the locality where they are
constructed; there is tendency for
the river to diminish its area of cross
section below them; they have to be
protected by levees of the same d.
mansions as the river itself: and
there IS danger, if the outlet is made
sufficiently large to be of practical
value, that the river may abandon
its present channel and adopt that
of the outlet.
Diversion of Flood Waters Into
Channels Parallelto the Main River
The maximum food discharge of
the Mississippi river exceeds two
million second feet, while it dis
charges about one million second
feet at bank full stage. A wide
channel which would discharge the
excess food waters would require AL
area Of cross section equal to that of
the river itself at bank full stage,
and with the same characteristics as
to depth and velocity.
Levees-Levees afford the only
practical means of preventing the
damages which might be caused by
floods in the lower Mississippi valley
They have been successfully en-
ployed on European rivers, and are
the only means of flood prevention
of large rivers that have been tested
or if tested has not failed. To res
train floods like those of 1912 and
1913 viii require in the existing
levee line about twice the yardage
now in place.
Appropriations Pending Investigations
Thirty years experience with Con-
gress has taught me that when that
body begins to investigate it is liable
to cease to appropriate.
A scientific investigation of all the
problems of river hydraulics, and
their proper coordination may be
exceedingly desirable, but to make
such an investigation necessitates an
accurate survey, and such surveys
cost money and require considerable
time for their execution.
The survey of Austria cost $500
per square mile, that of Great Brit
ain 1856, and that of Germany $40.
The survey of the Mississippi river
by the Mississippi River Commits
sion exceeded $50 per square mile,
and has been in progress over thirty
years. II is none too accurate for
the solution of all the problems in
hydraulics which can arise on a riv-
er and if such a survey were extend
ed over the entire United States it
would cost over S100,000,000. 1t is
also very questionable if there are
enough surveyors in the country TO
complete such a work in ten years.
This matter appears to be a fitting
occasion to emphasize the fact that
if Congress will appropriate the re-
quisite funds, the Mississippi River
Commission can construct levee
line which will give adequate pro-
lection to the Mississippi valley be-
fore any body of experts can collect
the data necessary to even prepare
an intelligent report on a scientific
coordination of the hydraulic prob
lens which may arise in the rivers
of the United States.