Humans largely control the flow of water in New Mexico. As discussed elsewhere in this book, nearly all major rivers are dammed, with countless irrigation districts and numerous muni cipal ities diverting water to maximize human use. Water resources are fully alloc ated and water use is strictly enforced. Pressures con tinue to mount as efforts to adju dic ate river sys tems con tinue. This current legal and water management framework was not built to protect threatened and endangered species, which represent rel at ively new and potentially signi fic ant players in the com peti tion for limited water resources in New Mexico. State and Federal laws and regulations, most notably the Federal Endangered Species Act of 1973 (ESA), and its associated regulations, provide a range of protec tions to endangered species (16 U.S.C. §§ 1531-1544; 50 CFR § 13-424).1 ESA protections can take the form of species and habitat conservation meas ures that affect water alloca tion and use, such as requirements to provide min imum water flows for a species in a river. Any requirement to provide additional water for endangered species conservation has the potential to result in a conflict with exist ing water uses or water rights holders. While conflicts between endangered species and existing water uses have resulted in changes in water management in New Mexico, a large scale realloca tion of per manent water rights to species protection has not occurred. Rather, short and long term leases of water, one time releases, water efficiency programs, and efforts to secure storage for endangered species have all been tested as methods to conserve listed species and their habitats. A wide range of management strat egies have been tried, varying from small scale permit riders to legal de cisions, to cooperative agree ments and memorandums of understanding, to congressional mandates. Coopera tion among management agencies has resulted in the de velopment of two large
scale multi species water management programs: the San Juan River Basin Recov ery Implementation Program (RIP) and the Middle Rio Grande Endangered Species Collaborative Program (Collaborative Program). These programs assist with co ordination and management of human and species water inter ests in New Mexico. Nonetheless, signi fic ant un cer tainties remain about the extent to which species conservation under the ESA may affect water alloca tion and use in New Mexico in the future, as well as the ultimate eco nomic costs of such conservation measures. This chapter explores:
1. regu latory mech an isms that give listed threatened and endangered species the potential to affect water alloca tion and use in New Mexico;
2. approaches to measuring the costs and bene fits of species protection efforts; 3. un cer tainties in ESA requirements as well as future impacts on water alloca tion
and use; 4. the role that listed species protection has played in water alloca tion de cisions to
date in New Mexico, focusing on the examples of the Rio Grande silvery minnow, Colorado pikeminnow, and razorback sucker; and
5. outstanding issues for future analysis.