Important Project Facts

Background and Proposed Action

The Arizona Water Settlement Act of 2004 (AWSA) ratified the Consumptive Use and Forbearance Agreement (CUFA) signed by Gila River users downstream of New Mexico. The CUFA details the conditions that must be met for New Mexico to be able to divert water from the Gila River and its tributaries in New Mexico, including the San Francisco River. The Colorado River Basin Project Act of 1968 as amended by the AWSA requires that Central Arizona Project (CAP) water be delivered to some downstream users in Arizona in exchange for consumptive use in New Mexico.

The New Mexico CAP Entity (Entity) Proposed Action is to establish the NM Unit through a series of water diversion, storage, conveyance, and delivery components. The Proposed Action would allow the Entity to divert and use a portion of the 14,000 acre-feet (AF) of water allotted under the AWSA, while not precluding future development of the full amount of allotted water. Reclamation and the ISC are preparing the NM Unit draft EIS to analyze the impacts of the project alternatives for construction, operation, and maintenance of the NM Unit. Chapter 2, Alternatives, of the NM Unit draft EIS discusses the Entity’s Proposed Action in detail.

Purpose and need for the NM Unit

The purpose of the Proposed Action is to develop an NM Unit to allow for consumptive use of water from the Gila River, its tributaries, or underground water sources in southwestern New Mexico, diverted in accordance with the CUFA pursuant to the terms of the AWSA. All of the water development would be for the benefit of the Entity—the project proponent. The NM Unit is defined in an agreement executed on November 23, 2015, and includes the necessary compliance with federal environmental regulations.

The needs for the Proposed Action are as follows: (a) to develop water for delivery at the times, locations, and quantities that would improve agricultural use within the Cliff-Gila, Virden, and/or San Francisco River Valleys; and (b) to provide capability for future expansion for the beneficial purposes authorized by the Colorado River Basin Project Act of 1968  and the AWSA. The Proposed Action identified in the NM Unit draft EIS is needed for agricultural use and does not include or preclude the independent development of subsequent projects to address these future needs. Future projects involving water developed pursuant to the AWSA and the CUFA would be subject to all environmental compliance required by law.

Existing Conditions

The three locations of project infrastructure considered in the NM Unit draft EIS have long histories of agricultural use, with agricultural water diversions from the Gila and San Francisco Rivers for over 100 years. The lands and river flows in these areas have been modified and disturbed by past and ongoing actions. Additionally, there are no current legal provisions or facilities to store water from the rivers allocated by adjudication or decree.

• Gila River (Cliff) location: Water is currently shared among three ditch associations for flood irrigation. Adjudicated water* is accessed at three diversion points by using bulldozers in the riverbed and creating temporary “push-up” diversions that feed ditches with head gates and gages downstream from the points of diversion. Push-up diversions are subject to washouts, temporarily precluding their use for irrigation and delaying repair. During low-flow periods, when there is not enough water in the river to supply all irrigators, the community rotates the watering of their fields.

• Gila River (Virden) location: Decree water** is conveyed from the Gila River into the Sunset and New Model canals via two permanent, low-profile diversion structures. The Virden location has the most robust agricultural practices and most diverse crop mixes of the three project areas, employing flood irrigation as well as sprinklers and drip irrigation, but still faces flow fluctuations and dry-ups.

• San Francisco River (Alma) location: Adjudicated water is diverted at four points from the San Francisco River via two push-up diversions and two permanent diversions, respectively feeding the Spurgeon Ditch #2 and Thomason Flat Ditch, and the W-S, Pleasanton East-Side, and Pleasanton West-Side Ditches. During low-flow periods, the operators coordinate diverting their adjudicated water.

*Adjudicated water—Gila and San Francisco River water in New Mexico adjudicated pursuant to the 1964 U.S. Supreme Court Decree in Arizona v. California and state adjudications. 

**Decree water—Gila River water adjudicated pursuant to Globe Equity Decree No. 59, dated June 29, 1935. 

Project vicinity map

Project Components

The NM Unit project components include various potential methods for water diversion, storage, conveyance and delivery. The draft EIS evaluates a variety of project components through the different alternatives, including the following:

• Surface water diversion structures are proposed on the Gila and San Francisco Rivers, including Obermeyer pneumatic gate, fixed crest weir or rock vane weir structures.

• Proposed storage facilities include surface-storage ponds sited off the mainstem of the rivers that would receive water directly from ditches via gravity flow or pumping.

• An aquifer, storage and recovery method that uses infiltration of surface water into an underground aquifer for later recovery and use via conventional wells is also evaluated.

• Production well are evaluated under some of the alternatives.

• A storage dam or reservoir on the mainstem of the Gila or San Francisco Rivers is not considered; however, an off-stream reservoir is evaluated near the San Francisco River.

• Proposed conveyance and delivery components would emphasize improvement and expansion of existing canals and ditches to minimize surface disturbance and increase water efficiency.

Next Station: Project Alternatives

For more information on the draft EIS, visit the project website or email NMUnitEIS@empsi.com.

You can also contact Sean Heath at Reclamation (623-773-6250) or Ali Effati at ISC (505-827-5801).

To be added or removed from the mailing list, email NMUnitEIS@empsi.com.