WSP10867

• File Number: 8278.400
• Description: Title I - Mexican Treaty
• Basin: Colorado Mainstem
• Date: 3/1/1962
• Author: IBWC
• Title: Mexican Water Treaty -Appendix E -Water Supply
• Water Supply Pro - Doc Type: Publication

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Estimate
Year
1922
1929
1934
1937
1944

Source
Senate Document 142
Senate Document 186
U.S. B.R. Report
Jacobs & Stevens Report
U.S.B.R. and LB.C.

Period of
years used
1903-1920
1895-1922
1897-1922
1902-1937
1897-1943

Annual Average
Virgin Flow
(acre-feet)
18,110,000
18,380,000
18,171,000
17,850,000
18,131,000

These figures were presented, according to Mr. Lawson, "

. to pOint out

the small amount of difference in the estimates from separate sources, of the virgin

or reconstructed flow of the river at Yuma, Ariz." At page 75 Mr. Lawson introduced

a hydrograph of the Colorado River at Yuma, Arizona for each year from 1902 to 1944.

The purpose of exhibiting the hydrograph was explained by Mr. Lawson as follows:

"We exhibit it because it shows those great variations in an
uncontrolled river, one without storage works until the year 1935,
when the Boulder was put in operation; it also shows the flattening
of those peaks of discharge where floods that formerly passed down
through Mexico are now stored back of Boulder Dam in a reservoir;
1901 and 1902 saw the first water go into Imperial Valley. That came
about from a filing made on the Colorado River, which filing was for
the purpose of obtaining the use of 10,000 second-feet of water for
use, as the filing states, 'in the United States and in Mexico.'
Following that filing a canal was constructed with headworks in the United
States, . . . , known-a-s-the-A:lamo-Ganal-;-'f-hi-s--cana'l-was-constructed
by the California Development Co., later operated and taken over
by the present Imperial irrigation district.
"The concession was granted by the Mexican Government under
the condition that one-half of the flow of that canal would be available
for Mexican use.
"The year 1905 was one of great disaster. Floods from the Gila,
beginning Thanksgiving of that year, put a flood discharge into the
river that finally found its way into Mexico and into the Imperial Valley.
In the 2 years that the river ran in that direction, leaving its course
to the Gulf of Mexico, it formed a lake in southern California with
about 400 square miles of area.
"The protection of lands from overflow in the Imperial Valley of
the United States at that time, as they are now, lies in Mexico. The
topography is such that much of the Imperial Valley and the Mexicali
Valley area is below sea level--at one time the arm of the Gulf of

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