WSP04312

• File Number: 8278.400
• Description: Colorado River-Colorado River Basin Water Quality/Salinity-Title I-Mexican Treaty and Minute 242
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 3/25/1944
• Title: Mexican Treaty-The Department of State Bulletin-Vol X-No 248-Publication 2089
• Water Supply Pro - Doc Type: Publication

00').1 '-;"7
(. ;t I

,
I

,
,
,

I~

American Republics,

II

WATER TREATY BETWEEN THE UNITED STATES AND MEXICO
'By Oharles A. Timm 1

The signature'on February 3, 1944 of the treaty
relating to the conservation, control, distribution,
and uso of the available water supply of the Rio
Grande below Fort Quilman, Texas, and of the
Colorado and Tijuana Rivers marked the culmi-
nation of nearly a ceulury of diplomacy relating
to these streams. 'Vhen it is considered that the
people, ~ommunities, industries, and agriculture
along the two thousand miles of this bOlmdary
are dependent to a very large degree upon the
water supply of the Colorado River and the Rio
Grande, it will be readily understood that this
treaty is one 'of tremendous importance.
A few basic facts regarding the boundary region
and the basins of the Colorado River and the Rio
Grande (see !'laps, PI" 283, 286, and 289) may be
useful in understanding the scope of the provi-
sio!,s of this treaty. Along the boundary ,are
found, on the United States side, the States of
California, Arizona, New Mexico, and Texas;
and on the Mexican side; the Territory of Baja
California and the States of Sonora, Chihuahua,
Coahuila, Nuevo Leon, and -Tamaulipas. The
basin of the Colorado River covers un area
of 244,000 square miles and includes parts of
Arizona, California, Colorado, N evada, New
Mexico, Utah, and Wyoming in the United
States and a small part of Baja California and
!?onora in Mexico. The seven States of the
Colorado River Basin in the United States are
divided for practical purposes into the npper basin
(Colorado, New Mexico, Ut~h, ,Wyoming) and the
lower basin (Arizona, California, Nevada), The
basin of the Rio Grande covers approximately
180,000 square miles in Colorado, New Mexico, and
Texas on the United States side and Chihuahua,
Coahnila, Nuevo LeQn, and Talllaulipas on the
Mexican side. Both of these rivers rise in the high
mountains of Colorado, and most of their water
supply is derived from precip,tation in the form
of rain or snow in the mountainous regions of the
headwaters of the main streams and their tribu-
taries. There is very little rainfall'in the lower

zsz '

basin of the Colorado River, and even in the case
of the Rio Grande tho relatively heavy rainfall at
the mouth adds little water to the river, which mllst
depend for the most part on the run-off from
its main tributaries--the Conchos and San Juan,
Rivers in Mexico and the Pecos and Devils Rivers
in the United Stutes. It is the basins of these two
rivers, together with the basin of the diminutive
Tijuana and the territory in the region of the nearly
700 miles of strictly land boundary that will be
'affected in many ways by the terms of the treaty
in'question and that require, for their greatest pos-
sible development, the cooperative endeavors of the
United States and Mexico. The basis for this co-
operation is carefully laid in the provisions of this
treaty.
The treaty itself is but the latest of a long series
of United States-Mexican conventions relating to
the Rio Grande and tbe Colorado, The treaties of
February 2, 1848 (9 Stat. 922) and December 3,
1853 (10 Slat, 1031) defined certain parts of these
rivers with reference to the boundary and regulated
the use of their waters for purposes of navigation~
Aside from some conventions between 1880 and
1890 which related to the land boundary, the next
treaty concerning the boundary was that of N Q.
vember 12, 1884 (24 Stat. 1011), which resulted
from the difficulties caused by accretive and avnl-
sive changes in the Rio Grande and the Colorado,
This treat.y defined the general laws of accretion
and avulsion to be applied t~ the boundary rivers
and prescribed the rules to regulate or control
artificial changes in their chal!nels, monuments on
bridges across them, and property rights on cut-
offs caused by avulsive changes in the river chan-
nels. The need of an international body to execute
the provisions of the treaty of 1884 led to the sign-
ing of the treaty of March 1, 1889 (26 Stat. 1512),
which provided for the organization, jurisdiction,
and authority of the present International Bound.
ary Commission, United States und Mexico.

. The author of this article Is a DivisIonal AssIstant In
the Division of Mexican AJrairs, Department .ot State.