Editor's Note: This is part 2 of a multi-part series of articles on the Interstate Stream Commission staff quarterly meeting in the area about the Arizona Water Settlements Act process. The meeting was held Monday, April 15, in the evening, at Western New Mexico University.


Jeff Riley, a civil engineer, who is the chief of Design and Construction, and Mary Reece, study manager for the New Mexico Unit, Central Arizona Project Program Development Division, of the Phoenix office of the U.S. Bureau of Reclamation, gave a presentation on their studies of diversion and storage sites and cost-benefit analyses.

 Riley explained that Reclamation had received a request from the ISC to do appraisal level work from engineering and cost estimate viewpoints using existing data. "We were tasked with economic analyses of the Tier-2 approved project proposals," Riley said, "as well as the assessments of diversion and storage Tier-2 projects."

The engineering analyses on the diversion and storage projects include the Hidalgo County, Deming and Gila Basin Irrigation proposed projects.

Reece said Reclamation is looking at all 16 proposals and doing a cost benefit analysis of each, along with the regional impact of each of the 16.

"We will do our best to put the benefits into dollars," Reece said. "How are we doing it? Some proposals have detailed costs estimates. Benefits transfer means comparing the proposals to similar ones in other areas. Avoided costs are considered those that help to avoid other costs in other areas."

To a question, she replied that ecosystem services are included in the cost benefits.

"I am working with the economic folks in the Denver Reclamation office," Reece said. "Included in the analyses are recreation, ecosystem benefits, municipal water supply and erosion control.

"We are focusing on benefits right now, because they are harder to quantify," Reece said. "With potential regional impacts, we are looking at cost data in each one."

An audience member asked how Reclamation figures costs over what is available in the AWSA.

"In each project, we are looking at the benefits," Reece said. "Often benefit to cost is greater than 1. What we are doing doesn't look at who will pay."

Riley went into the diversion and storage analyses. "Reclamation was also asked to look at other diversion points that had potential. We did site visits in November and March. Our initial data gathering is complete. Right now we are focusing on three diversion proposals."

The Gila Basin Irrigation Commission proposal includes upgrading existing diversions and storing the water in the underground alluvium, as well as in small reservoirs, such as ponds.

The Hidalgo County proposal includes diversion and conveyance, with storage at Schoolhouse Canyon and a smaller storage near the Arizona state line. The water will be for agricultural and municipal use.

The Deming proposal is a surface water diversion and a small storage in Mogollon Creek, with subsurface diversions and storage in a Mangas reservoir.

Riley was asked what a subsurface diversion was.

"It is primarily large-diameter pipes from the alluvium and the water is piped out into the storage," Riley replied.

Craig Roepke, Interstate Stream Commission Gila Project manager, described it as a "horizontal well."

An audience member asked about the uses for each project.

The GBIC one is primarily for agricultural use; the Hidalgo County proposal is designated for agricultural, municipal and industrial use; and the Deming proposal's Mogollon storage is primarily for environmental mitigation to keep flows high enough for endangered species, with some use for agriculture; and the Mangas reservoir for municipal and industrial use.

Donna Stevens of the Upper Gila Watershed Alliance said that at a meeting in Deming in January, Riley had said Mogollon Creek was not included in storage, but now it is in the amended Deming project.

Riley said Reclamation was trying to stay away from large drainages with significant impact on the main stem of the Gila. "A lot of times, there will be a lot more than 350 cubic feet per second flow on Mogollon Creek. Once the reservoir is filled up, spillways can handle the overflow. Even before the reservoir if filled, the amount of water stored is still limited to 350 cfs, but once the flood goes by, you have to release anything above the 350 cfs amount."

A questioner asked if the pipeline from Bill Evans Lake to Tyrone might be part of a pipeline down to Deming. Yes, the pipeline is being considered.

Martha Cooper of The Nature Conservancy said, at the Deming meeting, Riley had said the slotted pipe infiltration was not feasible, and that's why previously it had been decided not to look at it.

"We're always going to run the numbers," Riley said. "Maybe I confused you before."

An audience member asked how large the proposed Mangas Reservoir and the pipeline over the Continental Divide would be, about evaporation loss, and how deep the reservoir would be and on whose land it would be built.

Riley said a lot of the answers could be found in the proposal on the nmawsa.org website. The surface area would be 5 to 10 times larger than Bill Evans Lake and 100 to 150 feet deep. The answer to whose land is also in the proposal.

A questioner asked about paying for evaporation, with an estimate of $2 million a year to pay for the water, and the taxpayers paying for it.

"If New Mexico holds back 14,000 acre-feet of water, we have to pay the $2 million," ISC Deputy Director Craig Roepke said. "'We' is the New Mexico Central Arizona Project entity water users—those who contract for it."

"Sen. John Arthur Smith asked for taxpayer-funded capital outlay of $25 million for a pipeline," an audience member said. "I think there is a lot of ambiguity."

Roepke said: "I cannot control politicians."

Another meeting participant asked what the impact would be on endangered species, such as the loach minnow.

"Those issues are all addressed in the National Environmental Policy Act and Environmental Impact Statements future phases of this project," Riley said.

Reece clarified by saying that during the appraisal level process, "we will address if endangered species will be impacted."

An audience member asked if Reclamation is required to look at climate change.

Carol Evans, Reclamation wildlife specialist, said it is mandated, and Reece said but it may not occur until during the NEPA process.

The rest of this presentation will be covered in a subsequent article.