A Case Study of Water Sharing in the San Juan Basin

A Professional Project submitted in partial fulfillment of the requirements for the degree of Master of Water Resources, Water Resources Program, University of New Mexico.In times of shortage, how should New Mexico’s scarce water supply be allocated? New Mexico’s prior appropriations doctrine gives a temporal preference of “first in time, first in right,” as the rule for allocation. Unfortunately, in most basins, we do not know with certainty who that “first” is, because rights have not been adjudicated. In 2004, the New Mexico Legislature passed Active Water Resource Management (AWRM) legislation which codified the Office of the State Engineer’s (OSE's) authority to administer water rights in advance of adjudication if needed. The OSE promulgated general regulations in 2004 implementing the legislation and district specific regulations for seven priority basins are forthcoming. Both the general and proposed district specific regulations allow for alternative administration, which consists of water sharing agreements, which include shortage sharing. Shortage sharing basically allows all water rights users in a particular basin to share the pain of low water years, ensuring that everyone gets a little water. This contrasts with traditional priority date based administration in which senior water rights holders get their full allocation of water before junior holders get any. While the AWRM as a whole has been controversial and further implementation bogged down in litigation a series of water sharing agreements have been successfully negotiated in the San Juan Basin. The San Juan agreement covers how to allocate water in the basin in advance of the adjudication process, and also includes provisions for water sharing during drought years. Factors leading to the agreement’s success include the nature of its administrative structure, its comprehensiveness, its flexibility, and the nature of its water allocation procedures. This is consistent with other research into interstate water sharing agreements. In my paper I will first discuss the background of traditional priority administration and water adjudications in the state of New Mexico, as well as delve into the nature of the AWRM alternative, which serves as the basis for the formation of shortage sharing agreements. I will next discuss some of the literature on large interstate agreements. I will then derive principles from them that can be applied to smaller local water sharing agreements. Finally, I will apply these to the San Juan Basin agreement, iv v and discuss whether the agreement has been successful or not, and whether it could be used as a model for other local water sharing agreements. I conclude that although adjudications are absolutely necessary and traditional priority date based administration will likely continue to be the most common method of water allocation in New Mexico, water sharing agreements in advance of adjudications can be useful tools for dealing with the Western United States’ water “crisis.