Paper: Sources of Controversy in the Law of the #ColoradoRiver: An Upper Basin View — Lawrence J. MacDonnell #COriver #aridification

Colorado River “Beginnings”. Photo: Brent Gardner-Smith/Aspen Journalism

Click here to read the paper. Here’s the introduction and summary:


The first two decades of the 21st Century have been characterized by prolonged periods of drought in the Colorado River Basin, causing some to argue that the region’s hydrologic system has shifted into long-term aridification. One effect has been to highlight the disparity between the amounts of water allocated for use under various legal arrangements and the physical availability of water, even in a system with over sixty million acre-feet (maf) of storage. This prolonged and deepening shortage of water also highlights other disagreements in the legal framework governing uses of the system’s total water supply. Serious disagreements respecting key provisions of the Law of the River were largely avoided when the system contained enough water to satisfy all interests. That is no longer the case. The purpose of this working paper is to explore some of the uncertainties in the Law of the River most likely to cause conflicts in times of water shortage and to consider ways for their resolution. The paper concludes that some long-standing assumptions about aspects of the Law of the River must give way to the realities of growing water scarcity. The paper begins with a brief summary of the conclusions from each of the six areas of uncertainty.


1. Uncertainties Concerning Mainstream Water Use Entitlements in the Lower Basin Interpretation: Consumptive uses of water from the main Colorado River for the three mainstream states are not a fixed allocation but aspirational and adjustable according to water availability after accounting for water for Mexico and losses and need to be adjusted accordingly.

2. Uncertainties Respecting Uses of Water from Lower Basin Tributaries Interpretation: All beneficial consumptive uses of tributary water in the Lower Basin are included within the Articles III (a) and (b) apportionment and need to be fully identified and accounted for annually. The effect of these uses on water availability in the main Colorado must be taken into account. Uses exceeding 8.5 maf/year may constitute a violation of the Law of the River under certain circumstances such as if their existence causes a failure to meet treaty obligations with Mexico.

3. Uncertainties Respecting the Status of Article III (b) Water
Interpretation: Authorization for the Lower Basin to increase its consumptive uses an additional one million acre-feet (maf) resulted in an agreement limiting the Lower Basin to total protected consumptive uses of 8.5 maf/year, including those in the tributaries. Uses exceeding 8.5 maf are contingent and need to be identified and managed, if necessary.

4. Uncertainties Respecting the Meaning of Article III (d) in an Era of Climate Change- Induced Water Shortages
Interpretation: The Upper Basin’s obligation not to deplete flows at Lee Ferry below 75 maf over consecutive ten-year periods (75/10) must take into account climate-change-induced reductions in water availability unrelated to Upper Basin depletions and find more flexible ways to satisfy this obligation that reflect actual water availability.

5. Uncertainties Respecting the Sources of Water to Satisfy the Mexico Treaty Obligation
Interpretation: The traditional view that the Upper Basin has an obligation to provide 750,000 acre-feet per year to meet the Treaty obligation to Mexico needs to be reconsidered when Lower Basin uses exceed 8.5 maf/year, when Mexico adjusts its delivery requirements to reflect shortages, and in view of the fact that, in some manner, the treaty water is a national obligation.

6. Uncertainties Respecting Uses of Tribal Water Rights, including Existing but Unquantified Rights
Interpretation: Tribes with reservations in the basin have rights to more than 20% of the system’s water. The states and the United States should search out opportunities to enter into voluntary, compensated agreements with willing tribes to forego uses of portions of their water rights as needed to help maintain and increase system water.

John Fleck takes a look at the uncertainties in this post on Inkstain, “Sources of Controversy in the Law of the River – Larry MacDonnell.”:

As we lumber toward a renegotiation of the operating rules on the Colorado River, one of the challenges folks in basin management face is the differing understandings of the Law of the River. There’s stuff we all know, or think we know, or stuff Lower Basin folks think they know that Upper Basin people may disagree with, and stuff Upper Basin folks think they know that Lower Basin people may disagree with.

Larry MacDonnell, one of the Law of the River’s great legal minds, has written a terrific treatise to help us untangle this. It’s clearly written from an Upper Basin perspective (“Yay!” said the guy – me – who drinks Upper Basin water!), so Lower Basin folks may disagree with some of what Larry is saying. That’s OK, the important thing is to understand that the answers to these questions are not given – that there are genuine disagreements on this stuff, and the negotiations to come need to wrestle with these questions.

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