Brownsville herald. [volume] (Brownsville, Tex.) 1910-current, 1929-02-24
MENACE FROM

A@4AAA4lGU 4IUm page 0UG.l
Eanizstfon or Valley engineers and
which was financed by remission
or state taxes to Hidalgo and Cam
eron counties, has been the subject
OF much comment In the engineer
ing world, and win be adopted on a
greatly magnified scale In con-
struction Of the Mississippi flood
control system.
The plan, in brief. Is 70 take the
surplus water from the river be-
fore 1t reaches the low delta sec
ton and discharge 1t into the Gulf
through natural and artificial
~floodways. In other words, 10 re-
move the menace before IL becomes
q menace. That the Valley system
viii accomplish this IS the unani-
nous verdict Of engineers who are
familiar with the Rio Grande and
the problems II presents.
AS the Rio Grande flows toward
the Gulf the banks gradually lower.
The riverbed at Mission will carry
double the volume of water that
can be carried at Brownsville with
out overflow. Also the Rio Grande
In the delta section occupies the
highest part Of the terrain in its
immediate vicinity, drainage being
away from the river, the result Of
gradual building up OF the river
bed bv silt deposits.
Remove Surplus Waters
The flood control system pro-
vides for removal of the major part
OF the surplus water before it
reaches the lower delta section.
The two inlets are provided, one
hear Mission and the other near
Hidalgo. the surplus water being
directed through a leveed channel
TO the series OF resacas which par
allel the Rio Grande In Hidalgo
county. The water is carried east
ward through Llano Grande lake to
n point near Mercedes, where it Is
divided. approximately 40 per cent
going eastward through a leveed
channel which follows the natural
drains to the Laguna Madre. The
other 60 per cent will be discharg-
ed through the Arroyo Colorado,
the great natural drain Of the VAL
ley. Another floodway Is provided
through the Rancho Viejo resaca
near Brownsville. and the system
on the Mexican side will take care
of a great volume Of the surplus
water.
Extending from Mission TO sew
eral miles below Brownsville, the
secondary line Of defense-the river
levees-present an almost impreg-
nable obstacle to invasion OF Rio
Grande waters. Only during abnor-
NAL floods. such as occurred in
1922. will their strength be tested.
rs the discharge system, which VIII
carry off the surplus water Of the
average flood, will relieve pressure
at all points below.
The huge ~floodway, which par
allels the Rio Grande from Mis-
sion to Mercedes. Is designed to
carry approximately 10000 second
feet, OF which $4,000 second feet
will be discharged through the
north floodway and 10000 through
the Arroyo Colorado. The Rancho
viejo floodway will discharge 5000
second feet and the Mexican sys-
tenn $4,000 TO 10000, according to
the height OF water. The riverbed
at Brownsville will carry approx
mately 10000 second feet before
heavy pressure Is placed on the
lower river levees. These various
fioodways and the river provide for
approximately 10000 second feet,
or the estimated volume Of the 1922
flood.
Conservation i'm Mexico
Another factor which will prove
valuable in connection with flood
control In the Valley Is the con-
servation project now under way
on the Salada in Mexico. where ar
surrounding dam is being con
structed. Similar works on the San
Juan are contemplated in conrec-
ton with irrigation projects. and
the La Boquilla dam on the Con-