When the Central Arizona Project was authorized by Congress in 1968 folks recognized one very important fact…..the Colorado River was divided up allocating 15 million acre feet (7.5 million acre feet to the Upper Basin states and 7.5 million acre feet to Arizona, California and Nevada) plus 1.5 million acre feet to Mexico via treaty and that the river could not reliably provide 16.5 million acre feet a year to all the users.
Before all the current hoorah about global warming it has long been recognized that the Colorado River was divided up based on a too short period of history. The allocations were based on some of the wettest years in centuries.
Subsequent studies of the historical climate in the basin shows that drought is much more frequent than originally assumed in the 1920’s and can last hundreds of years.
We don’t need the fear of global warming to understand climate variability and bite the bullet and make some necessary adjustments.
Back in 1968 the architects of the CAP understood that the river would not support the existing allocations.
There is a “sleeper” provision in the CAP authorization called the “Mexican Treaty Obligation” that is just now coming to fruition:
Public Law 90-537
90th Congress, S. 1004
September 30, 1968
COLORADO RIVER BASIN PROJECT
SEC 201…..the Secretary of the Interior shall conduct full and complete reconnaissance investigations for the purpose of developing a general plan to meet the future water needs of the Western United States. Such investigations shall include the long-range water supply available and the long-range water requirements in each water resources region of the Western United States. Progress reports in connection with these investigations shall be submitted to the President, the National Water Commission (while it is in existence), the Water Resources Council, and to the Congress every two years. The first of such reports shall be submitted on or before June 30, 1971, and a final reconnaissance report shall be submitted not later than June 30, 1977; That for a period of ten years from the date of this Act, the Secretary shall not undertake reconnaissance studies of any plan for the importation of water into the Colorado River Basin from any other natural river drainage basin lying outside the States of Arizona, California, Colorado, New Mexico, and those portions of Nevada, Utah, and Wyoming which are in the natural drainage basin of the Colorado River.
SEC. 202. The Congress declares that the satisfaction of the requirements of the Mexican Water Treaty from the Colorado River constitutes a national obligation which shall be the first obligation of any water augmentation project planned pursuant to section 201 of this
Act, and authorized by the Congress. Accordingly, the States of the Upper Division (Colorado, New Mexico, Utah, and Wyoming) and the States of the Lower Division (Arizona, California, and Nevada) shall be relieved from all obligations which may have been imposed upon them by article III(c) of the Colorado River Compact so long as the Secretary shall determine and proclaim that means are available and in operation which augment the water supply of the Colorado River system in such quantity as to satisfy the requirements of the Mexican Water Treaty together with any losses of water associated with the performance of that treaty; Provided, That the satisfaction of the requirements of the Mexican Water Treaty (Treaty Series 994, 50 Stat. 1219), shall be from the waters of the Colorado River pursuant to the treaties, laws, and compacts presently relating thereto, until such time as a feasible plan showing the most economical means of augmenting the water supply available in the Colorado River below Lee Ferry by two and one-half million acre-feet shall be authorized by the Congress and is in operation as provided in this Act.
SEC. 305. To the extent that the flow of the main stream of the Colorado River is augmented in order to make sufficient water available for release, as determined by the Secretary pursuant to article II (b) (1) of the decree of the Supreme Court of the United States in Arizona against California (376 U.S. 340), to satisfy annual consumptive use of two million eight hundred thousand acre-feet in Arizona, four million four hundred thousand acre-feet in California, and three hundred thousand acre-feet in Nevada, respectively, the Secretary shall make such water available to users of main stream water in those States at the same costs (to the extent that such costs can be made comparable through the nonreimbursable allocation to the replenishment of the deficiencies occasioned by satisfaction of the Mexican Treaty burden as herein provided and financial assistance from the development fund established by section 403 of this Act) and on the same terms as would be applicable if main stream water were available for release in the quantities required to supply such consumptive use.
What this means is that in order to fulfill our treaty obligation to Mexico of 1.5 million acre feet a year, doing this will be a “national obligation”. That means any effort to augment the river’s water supply will not be based on a cost-benefit deal and repaid by just the Colorado River basin states. Meeting that treaty obligation will be national in scope and cost.
As one member of Congress noted back in 1968 “you’ve built a plank into the US Treasury”. Indeed, that is the case.
Note that the trigger for augmentation is not the 1.5 million acre feet owed to Mexico….the trigger is 2.5 million acre feet. Who gets the other 1 million acre feet? Los Angeles and Phoenix.
When the Mexican Treaty Obligation language was inserted into the CAP legislation no one had a clue how the river would be augmented. Maybe divert water from the Columbia River Basin? Washington Senator Henry “Scoop” Jackson got a provision added banning studies of a Colombia River diversion.
Would huge desalting plants be constructed on the California coast to replace their Colorado River supplies? That was and still is on the table. A giant desalting plant at the northern end of the Gulf of California? Indeed that is a possibility.
Buy out farms in Yuma and the Imperial Valley? Possibility. What is emerging is municipal interests funding irrigation efficiency improvements to reduce Imperial Valley agricultural water use for the benefit of cities.
Whatever the scheme turns out to be, 42 years ago the folks who put the CAP legislation together understood that 40 or 50 years out into the future a water crunch would come and the river would need to be augmented. They made sure that when that day arrived, it would be a national obligation to protect Mexico’s water supply, not just California’s and Arizona’s.
Note: I have been practicing water law since 1974 and before that I was a very junior member of Congressman Mo Udall’s staff and was in the room in 1967 when Arizona and California made various deals on the CAP such as the 4.4 maf guarantee to California and the inclusion of the Mexican Treaty Obligation into the legislation. I also served as a Commissioner on the Arizona Power Authority 1980 to 1984 and was involved in the reauthorization of Hoover Dam power agreements which funded $800 million of Arizona’s share of CAP costs.