BOARD00670

• Board Meeting Date: 3/26/2001
• Description: WSP Section - Colorado River Basin Issues - Delta and Inadvertent Overrun Accounting Policy Resolutions
• Board Meetings - Doc Type: Memo

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STATE OF COLORAD

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Colorado Water Conservation Board
Department of Natural Resources
1313 Sherman Street, Room 721
Denver, Colorado B0203
Phone: [phone]
FAX: [phone] MEMORANDUM
www.cwcb.state.co.us

Bill Owens
Governor

Greg E. Walcher
Exewtive Direclor

. Rod Kuharich
CWeB Direttor

'Dan McAuliffe
Deputy OirO!Ct\)r

Colorado Water Conservation Board Members

Rod Kuharich, Director R /:::::2--. '.
Randy Seaholm, Chief, Water Supply Protection tf~.:;-;t

DATE: March 14,2001

TO:

FROM:

SUBJECT: Agenda Item 25(e), March 26-27,2001 Board Meeting - Colorado
River Basin Issues, Colorado River Delta

Back~round

The purpose of this memorandum is to update the Board Members on Colorado River
Delta issues and recommend broad policy guidance. Staff last reported to the Board on
Delta issues at the November 2000 meeting. To briefly recap, relations with Mexico and
the protection and conservation ofthe Colorado River Delta (Delta) in Mexico have long
been issues. The 1944 Mexican Water Treaty (Treaty) obligates the U.S. to deliver 1.5
MAF of water to Mexico annually, except during declared surplus or shortage conditions.
Furthennore, the Treaty provides that Mexico shall acquire no right beyond that provided
by the Treaty to the use of waters from the Colorado River system. Subsequently,
Minute 242 to the Treaty was adopted assuring Mexico that the quality of Colorado River
water would be no more than 115 ppm, plus Of minus 30 ppm, over the salinity of the
river at Imperial Dam. A waste water drain (MODE) from the Wellton-Mohawk area of
Arizona to the Santa Clara Slough was constructed for the purpose of assuring this water
quality along with the Yuma Desalting Plant. Given the expense of operating the
desalter, the MODE has been the primary means of disposing ofthese saline returns,
which are not counted as part ofthe Treaty delivery unless treated by the desalter and
returned to the river. The untreated saline returns have had positive environmental
effects on the Slough.

Delta issues were discussed at some length during the development of the Lower
Colorado River Basin Multi-species Conservation Plan, but were appropriately left out of
that process. Subsequently, on May 18, 2000 the U.S. Secretary of Interior and the
Secretariat of Environment; Natural Resources and Fisheries of the United Mexican
States entered into the, "JOINT DECLARATION BETWEEN THE DEPARTMENT OF
THE INTERIOR (DOl) OF THE UNITED STATES OF AMERICA AND THE
SECRETARIAT OF ENVIRONMENT, NATURAL RESOURCES AND FISHERIES
(SEMARNAP) OF THE UNITED MEXICAN STATES TO ENHANCE