Climate change and the resulting changes in rivers flows pose significant problems for transboundary water management agreements. But a new paper by Heather Cooley and Peter Gleick at the Pacific Institute finds a hopeful model in recent tweaks adding flexibility in the face of drought to the “Law of the River” governing distribution of water from the Colorado River:
In 2007, the USA implemented the Colorado River Interim Guidelines for Lower Basin Shortages and Coordinated Operations of Lake Powell and Lake Mead (referred to as the “Interim Guidelines”). This agreement, developed in the eighth year of the worst drought in over 100 years of record keeping, establishes specific guidelines for reduced water deliveries among the seven Colorado Basin states under drought and low-reservoir conditions. These shortage guidelines, which were developed in consultation with the Mexican government, are triggered at specific reservoir water levels in major reservoirs on the Colorado River (Lake Mead and Lake Powell), thereby providing water users with some indication of the frequency and magnitude of these events. The Interim Guidelines also create a novel multi-year water augmentation and banking programme known as “Intentionally Created Surplus”, allowing lower basin water users to invest in extraordinary conservation efforts and store the water saved or generated by such efforts for delivery in future years. A related programme, called “Developed Shortage Supply”, creates similar mechanisms to generate and store water to be delivered during declared shortages, buffering the users against major reductions. These guidelines were drawn up among the USA Colorado Basin states and do not address deliveries to Mexico. Adoption of the Interim Guidelines, however, has provided impetus to Mexico and the USA to begin negotiations to determine the conditions that would prompt Mexico to accept reduced deliveries of Colorado River water, as well as potential mechanisms for adapting to such changes.
The paper is here (pdf) and Felicity Barringer has a nice writeup of some of the broader questions addressed.