Developing water management options along the Middle Rio Grande (MRG) requires recognition and public acknowledgment that pueblos hold the senior-most water rights on this river. These water rights are not subject to State law nor are they potentially governed by State administration. Instead, Rio Grande pueblos and other native tribes have inherent sovereign authority over their water resources, as granted by the U.S. Congress. These rights must be respected during regional water planning and management efforts.

It is important to recognize that in dry or low-flow years, pueblo water rights can be entitled to the largest proportion of the total surface water available for irrigation in the MRG.  As such, no effort to develop or implement MRG regional water planning can expect to be effective without active participation and representation from this key group of stakeholders. Careful consideration of their political, cultural, and technical issues must be a focus for their potential involvement in any such participation.

Irrigation flows for the Pueblos’ crop lands come from native flow in the Rio Grande with additional flow coming from native storage in El Vado Reservoir to help address potential shortfalls caused by low mainstem Rio Grande flows. Federally recognized and protected MRG pueblo water rights to irrigate more than 20,000 acres for the six pueblos along the mainstem in the MRG and within the MRGCD service area: Cochiti, Kewa (previously “Santo Domingo”), San Felipe, Santa Ana, Sandia, and Isleta pueblos.

There are also pueblos with lands along the Rio Jemez, a tributary to the MRG. In addition, Taos Pueblo, Ohkay Owingeh (previously “San Juan Pueblo”), and four Pueblos in the Pojoaque Basin tributary of the Rio Grande and Jicarilla Apache hold leases for San Juan-Chama Project water. Several Pueblos also use groundwater for domestic drinking water, casino use, and for irrigating golf courses and a vineyard.

The pueblos hold claim to several classes of water rights, including federal reserved Indian water rights and time immemorial water rights that arise from their original sovereignty, which include their Prior and Paramount (P&P) water rights. It is their P&P water rights that are most commonly the focus during MRG water management discussions. P&P water rights are recognized for the MRG pueblos and may be exercised for any native Rio Grande water flowing through or by the pueblo. P&P water rights are owned by each pueblo and these rights are not tied to particular parcels of land assigned internally to pueblo families.

Congress recognized and protected pueblo water rights in the Middle Rio Grande Conservancy District (MRGCD) Act of 1928 to include P&P rights for irrigation, domestic, and livestock uses. The 1928 act authorized the U.S. Department of Interior to contract with the MRGCD to also provide conservation, irrigation, drainage, and flood control for the MRG pueblo lands. The six pueblos in total have P&P rights to irrigate 8,847 acres. Pueblos also have the equivalent irrigation priority as non-Indian lands for newly reclaimed irrigated lands within the MRGCD. Reclaimed pueblo lands are not to exceed 12,600 acres, with the acreage defined to limit payment by the United States on behalf of the Pueblos for operation and maintenance (O&M) charges to MRGCD.

The U. S. Bureau of Reclamation (USBR) maintains storage for P&P water within El Vado Reservoir. Storage water volumes held in El Vado are based on a 1981 storage agreement and calculations by the “Designated Engineer,” who represents the Department of Interior (DOI) and is designated by Secretary of Interior through the Commissioner of Indian Affairs. This agreement originated with an Irrigation Committee that included representatives from the six pueblos, Bureau of Indian Affairs (BIA), and USBR. The Rio Grande Compact exempts Indian water rights. (Similarly, San Juan-Chama Water is exempt from the Compact.)

P&P water in El Vado is managed as a single pool for all of the six MRG pueblos; the storage capacity is not differentiated among the individual pueblos. Releases of P&P water from El Vado during the irrigation season can be called for by the MRG pueblos working with USBR and the BIA. Under a 1981 agreement the required storage quantities in El Vado for the six MRG pueblos are computed on a monthly basis for the upcoming irrigation season.

This 1981 agreement is designed to help protect the P&P lands from shortages during drought years, but complete protection is not guaranteed. It assumes that the pueblos are supplied first from the native flow of the Rio Grande, supplemented from El Vado storage only if the natural flow falls short of pueblo demand. When the water quantity computed for storage in El Vado for a particular month goes unused during irrigation season, it then reverts to the general MRGCD Rio Grande pool on the first day of the following month. This water then can become available for use by more junior water rights holders within the MRGCD, but also remains subject to applicable Compact constraints.

P&P water that is stored but not used during a given irrigation season loses its P&P designation. This water reverts back to the general MRGCD Rio Grande pool and then may be carried over by MRGCD to the next calendar year, depending on applicable Compact restrictions. Any such unused water that is discharged outside of the irrigation season (typically during November or December) becomes Rio Grande Compact water and therefore is not available to pueblo or other MRGCD irrigators the following year.

Whenever considering potential management options regarding irrigation efficiencies, it is important to recognize that some pueblos have cooperated with the MRGCD on infrastructure and operational improvements. These include concrete lining of ditches, installation of automated gates to ensure consistent irrigation water delivery, and coordination of irrigation water deliveries. Pueblo involvement with MRGCD includes having pueblo members elected to its board of directors from time to time

Source information for this summary came from the following:

• Chestnut, Peter. 1999. A Pueblo Perspective on the Rio Grande Compact. WRRI Conference Proceedings. https://nmwrri.nmsu.edu/wp-content/uploads/2015/watcon/proc44/chestnut.pdf
• Sanchez, Viola. 2007. Carryover Storage of Indian Prior and Paramount Water in El Vado. https://digitalrepository.unm.edu/uc_rio_chama/16
• Compiled notes taken during 2003 meetings of Pueblo, other tribal, and USBR representatives with the Water Acquisition and Management Subcommittee of the Middle Rio Grande Endangered Species Collaborative Program
• Comments and edits from Peter and Elizabeth Chestnut on an earlier draft are gratefully acknowledged in improving this summary