Evening star., 1923-12-18
bARRAGE TO TURN
DESERT T0GARDENS
Largest irrigation Project of
This Type in World
Planned in India.

News from India that the worlds
greatest barrage is to be laid down
in the Indus valley does not mean
that new world war Is in progress,
with an inferno of bursting shells.
but that Great Britain's engineers
are going about the peaceful business
of tanning a great river and adding
millions Of acres to the earth's till
able area.
What a barrage Is, and how this
latest of great reclamation projects
compares with the leading irrigation
works of the United States and the
lowing bulletin from the headquar-
ters here Of the National Geographic
Society:
Unlike the famous Assuan dam
across the Nile and such well known
American structures as the Elephant
Butte, Roosevelt and Pathfinder
dams. the heart of the Indus irriga-
ton system is to be a barrage, not
dam. Both barrages and darns work
toward the same ends-to help get
river water on the land-but they go
about it in somewhat different ways.
Rnises Water Level.
"The barrage is a low-dam. over or
through which the water continues TO
flow. It's function is to raise and
keep the water at a certain height,
so that part of IL will run or into
canals on the river banks. The re-
mainder goes tumbling over the bar
rage and on down the river bed. The
barrage is. In a word. a colossal elder
brother to the diversion weirs that
turn water from main canals into
minor channels.
"The dam. on the other hand. is pri-
marily storage structure that ere
ates a great reservoir in which the
entire flow for the year is held cap
tive until the dry season, when II is
needed in the valleys below. Then
the stored water is fed out Through
Sluices.
Few Barrnges in United states.
"The physical geography of the
United States is such that practlcaiIy
all it's irrigation development mas
been based on the use of dam made
reservoirs rather than on harrages.
Only one big barrage is a part OF the
many irrigation systems developed py
the United States reclamation service,
the So-called Laguna dam across the
Colorado river few miles above
Yuma, Ariz. This structure merely
makes a sort of a huge permanent
wave in the Colorado, but II is SUI
ficient to divert hundreds of thou
sands of gallons of water into great
canals which flow off along both the
Arizona and the California shores.
The Indus barrage, which Will be
built near Sukkur, in the Sind. VIII he
the greatest barrage in the Worid.
both in length-which Will be almost
a mile-and in the amount OF water
diverted Seven canals Will flow out
on the level created by the new struc-
ture and will furnish water estimated
to be enough to irrigate six million
acres OF land now. barren. This is a
region greater than the entire area
of Massachusetts.
HOnOrs in Dams.
1.-TWO OF the canals on the right
bank of the river will be wider than
the Suez canal. and one of the water
ways on the left bank will be nearly
half as broad again. The remaining
channels will be narrower. but viii
carry mighty streams themselves.
Among existing irrigation struc-
lures the Assuan dam across the Nile
is often pointed to as the greatest.
In point of length it probably is.
since it is one and a quarter miles
from abutment to abutment. It's LAG
feet of height, however. is overtopped
by at least Ave American irrigation
Idaho. 349 feet;
Shoshone, Wyo.. 328; Elephant Butte,
N NJ, 800; Roosevelt, AriZ.. ESQ. and
Pathfinder, Wyo., 2lS. In the matter
of the amount of water impounded,
world honors among artificial reser-
voirs should probably go to the Ele-
phant Butte dam. across the Rio
Grande river in New Mexico. Such
measurements are best made in the
number of acres the water would
cover one foot deep. The capacity of
the Elephant Butte reservoir is more
than $4,000 acres feet greater than
that created by the Assuan dam