Evening star., 1936-01-30
ENGINEERS STUDY
MODELS OF RIVERS
Flood Control Experiments
Employ Physical Laws and
Exact Data.

WCKSBURG, Miss, January 20 IN.
AN.A.).-One of the Oldest laws OF
mathematics and the basic formula In
hydraulics are today being applied in
laboratory for the practical purpose OF
making the nations streams and rivers
behave. The laboratory is that of the
United States Waterways Experimental
Station, located 6 miles from here.
The law is that which the 26-year-
old professor of mathematics, physics
and astronomy at the famed Universe
ty of Pisa demonstrated to the erudite
professors and group of students:
That velocity of freely falling body
through air is equal to the square root
Of twice the force of gravity times the
height from which it has fallen. This
law. also governs the flow of water in
streams and it remains the basic for
n1ula in the experiments Of group of
engineers as they construct concrete
miniature models of the rivers, harbors
and lakes Of the United States.
Nestled in the peaceful little valley
are stretches Of glistening concrete
models constructed on a scale to ex-
actly represent the bodies of water
With which the experiments are con-
cerned. The laboratory is the only in
stitution In the United States devoted
to the study Of rivers and harbors. It
was founded in 1880 by the War De-
partment Corps of Engineers and is
operated under the special jurisdiction
Of the president of the Mississippi
River Commission, who is in charge Of
all improvement work on the lower
Mississippi River and its tributaries.
Proportions Are Exact.
Hyradulic laboratory practice has
It's basis in what is commonly called
''the law Of similitudes." When re-
duced to its simplest form it means
that if a small scale model Of a river
or any other waterway be constructed
to dimensions proportionately to those
In nature, under similar conditions the
model will manifest similar phe-
nomena.
The hydraulic laboratory in cruci-
bic in which the river and harbors
engineer may test the practicability Of
his plans before they are put into e,e-
cution He submits his problems to
the experts at the United States Wa
terways Experimental Station and
from the data of recent surveys and
accurate maps of the locality they
construct a small scale model of the
territory affected by the proposed
works.
All linear measurements are made
TO the nearest $4,000 of foot, and
even trees and underbrush are repre-
sented. In this model. then, are con-
structed In miniature the features
which are being proposed for installa-
tion in the natural river. Water is
passed through it in quantities and to
heights corresponding proportionally
to its size with the original and the
effects and results which follow can
be reliably considered as accurate pre-
dictions Of what would occur should
the plan be tried on full sized SCALE
Many models are constructed out
Of doors, one of them being 602-mile
model of the Mississippi River, repre-
senting the stream from Helena, Ark,
to Donaldsville, La. It is the largest
hydraulic model ever constructed, say
the engineers. It's construction was
ordered by the President Of the Mis-
sissippi River Commission, Gen. Harley
Bascom Ferguson, in an effort to pre-
vent another such disastrous flood
10 the lower reaches Of the river, as
occurred In 1927.
Like 10000 Miles Of Valley.
The model contains 10000 square
feet Of concrete surface. It represents
m era of 10000 square miles of the
Mississippi Valley.
Throughout the area represented by
the model not only have all the river
channels been built to their exact
scale, but also levees, lakes, railroads.
highways and other typographical
features.
Since the institution of the flood
control program in the Mississippi
River, various Improvements have
been made with the object Of pre-
venting a reoccurrence of the catas-
trophe. These have included channel
dredging. placing of dikes, the reloca-
tion and raising of levees, and an ex-
tensive system of cut-offs. One of the
principal objectives Of the present
model Is to test the effectiveness of
al these works to determine whether
they will provide the protection for
which they were designed.
(CopyY1ght, 1886 North American News.
oaoer Al1fAnce)