[Editor’s Note: First off, sorry about the delay, but a dead computer will slow things down. This meeting addresses the questions from the entity members about the diversion yield report and starts the 30 percent engineering presentation.]
By Mary Alice Murphy
John Sikora of AECOM presented the diversion yield reports at the New Mexico Central Arizona Project special meeting held Sept. 25, 2017.
During and after his presentation he answered entity member questions.
He presented a hypothetical situation where in July the need is for 300 acre-feet at 10 acre-feet a day. "Do I have water available based on demand? With ASR (aquifer storage and recharge) only, we can realize 26 percent." He noted that the groundwater study that had been done by S.S. Papadopulos had not looked at ASR, but had studied the limits to the aquifer.
Entity Member Joe Runyan, representing the Gila Farm Ditch, noted that if water were to be utilized in the shoulder season, farmers could have cool season crops, like rye, beets and turnips. "We can innovatively change the ASR."
NM CAP Entity Executive Director Anthony Gutierrez asked if the analysis is solely on ASR, "how can it be improved with on-farm storage."
Sikora said the concept is for a single diversion for storage. "We can build a diversion that can withstand large floods." He noted that two ditches are on river right and one on river left. On-farm storage is because AWSA (Arizona Water Settlements Act) water needs to be more available on river left."
He said other alternatives include flood irrigation, which has pluses and minuses. One of the pluses is that it recharges the aquifer. "With ASR, you have to pump it. Does it make more sense to use sprinklers? A minus with flood irrigation is you're putting on more water than the plants need."
Gutierrez asked how ASR and storage relate to the overall yield. "Does it extend the surface water life for downstream?"
Sikora said the higher the yield, the more efficient it is. "It also improves the ecosystem. The advantage of flood irrigation is water comes back to the river and is good for aquatic life."
"A Gila diversion with only ASR increases reliability by diverting less," Sikora said. "The optimum, instead of 100 cfs is 50 cfs, which gives you more days to divert. ASR is a minimum reservoir with the water disappearing in two to three months.
"We need to find a way to extend the volume, because it doesn't make sense to take it in January and February," he said. "It will disappear before it's needed.
Sikora said a Mogollon diversion with storage in Winn Reservoir would give more control over when the water is delivered. The San Francisco with the Weedy Reservoir would meet the 1,000 acre-foot demand more consistently.
Howard Hutchinson, representing the San Francisco Soil and Water Conservation District said one concept members had looked at was to store water in one basin and have water sharing between the two basins.
"If we can tag or color the ASR water that comes into the Gila, we could move it into the San Francisco," Sikora said. "The average is 10,000 acre-feet annually, with a 3,000 acre-foot deman, which would leave 7,000 af coming back into the system."
Entity Attorney Pete Domenici Jr. noted that on page 12 of the report, it showed a significant amount diverted and not used. "Is that already in the ASR system?"
"It is returned to the river," Sikora said. "They divert more than they need, because they need a head on the water to irrigate. They are measuring through the head gate. They are not measuring what goes back through the 'waste ways.'"
Runyan said the irrigators asked for gages to measure the return, but the Office of the State Engineer said it didn't have enough money.
Allen Campbell, representing the Gila Hot Springs Ditch, said he has a dump gate for mud before it gets to the head gate. It dumps back into the river. "It is measured in and out. We run it all the time."
Paco Larsen of AECOM presented the 30 percent engineering report. "This part presents the alternatives." He described the history leading to where the concept is now. The 2016 report culminated in four alternatives, two of which were selected by the members of the CAP Entity. However, they were rejected due to land ownership issues later identified.
AECOM has gathered additional information after learning the entity intends for the water to be used primarily for agricultural consumption. Site visits took place. ASR was taken into consideration, and a yield model was developed.
"This 2017 report is an addendum to the 2016 report," Larsen said.
The entire 2017 report may be viewed at http://nmcapentity.org/documents/presentations/51-presentation-nmcap-final-sept-22-2017 . The 2016 report at http://nmcapentity.org/documents/presentations/11-nm-cap-draft-alternatives-report-070816
The scope of work included studies about on-farm pond water storage and ASR conceptual development; surface diversion locations, including an evaluation of a Mogollon Creek surface diversion, groundwater pumping; Upper Gila surface diversion; and San Francisco surface diversion.
Runyan asked if the ponds would be lined or unlined. Larsen replied: "Unlined for infiltration of the water. We want the ponds to be on the fringe of the aquifer."
Vance Lee, representing Hidalgo County, said: "In Virden, we would like to see some consideration for on-farm storage."
"It is as applicable in Virden as in the Gila Valley," Larsen said.
The design criteria developed for the report he presented include a demand for 3,000 additional acre-feet of water for consumption annually in the Gila Basin and a demand for an additional 1,000 acre-feet in the San Francisco Basin. A diversion that can be designed to divert 350 cubic feet per second of AWSA water and an additional 75 cfs for the Gila ditches and an additional 75 cfs for the San Francisco Basin. Conveyance in the Gila Basin will be 30/125 cfs per ditch and 75 cfs total for the San Francisco.
Larsen said scoring was done using the same criteria and methodology as in the 2016 report, encompassing engineering, construction, environmental and social criteria.
He noted that the information used was from historical records, but gages have different periods of record.
Three sensitivity analyses were completed for the 2017 report. The first was the same as the 2016 report, but in 2017, they considered average scores instead of maximum, and they adjusted sub-criteria scores to maximum credible weight for land acquisition and ecological impact sensitivity. The conclusion arrived at, in spite of minor changes to scores, made no significant change in ranking of alternatives.
Preliminary system alternatives took into consideration several significant factors, including scores, scalability, projects that have significantly different elements because minor adjustments can be made in any project, projects with phasing options and engineering judgment.
The first alternative he presented was Alternative 5—Mogollon plus Winn Reservoir plus the San Francisco Basin.
The option offers phasing, with elements for the Gila Basin and elements for the San Francisco Basin. Maps can be viewed in the report, as can a hydrogeological schematic.
Alternative 6 includes six on-farm ponds for ASR plus Winn Reservoir plus elements in the San Francisco Basin.
Alternative 7 is the same as Alternative 6, except it has one large infiltration pond instead of six ponds.
"Any of these can be phased," Larsen said.
B. J. Agnew, representing the Upper Gila Irrigation Association, said he was concerned about the on-farm storage ponds taking land out of production.
Larsen said better places can be found.
Campbell asked why Woodward land was not being considered for a diversion, as it was a shorter run.
Larsen said AECOM had looked at Woodward land and three other properties, but the land at the Gila Gage was the most suitable for a diversion. "The first four we recommended in 2016 haven't disappeared."
Referring to the scoring of the three newest alternatives, "they are virtually identical," Larsen said. "We call ASR transitory storage. We have to determine how much ASR will store."
The cost breakdowns are on page 30 of http://nmcapentity.org/documents/presentations/51-presentation-nmcap-final-sept-22-2017, with the phases and full build out.
Domenici asked about the costs and why they varied so.
Larsen said the Spurgeon Reservoir was quite a bit longer than others. "We like it better because it is closer to the heads of two ditches. With six Ranney wells, it will cost $149.2 million. Spurgeon would be a huge percentage of the cost." He said the range of costs were on the high, conservative end, and included 30 percent contingency.
"A diversion on the Gila can send to the east side or the west side of the river," Larson continued. "On the west side, we could pump downstream with gravity to pump up into Winn Reservoir or up to the diversion to go to the east side Ranney wells."
He said Winn would cost $169 million including construction and piping.
Domenici asked the pros and cons of the single pond versus multiple ponds. Larsen said the single pond would be more concentrated and the water would get into the aquifer faster. With the multiple ponds, aquifer recharge would be slower. "We are trying to hold onto water for the agricultural month. ASR will move through the system. If we don't take it out, it will end up in the river. We need to create groundwater as a whole."
Domenici asked how often the ponds could refill and infiltrate.
"Assuming a five-foot depth, it takes a couple of weeks to infiltrate," Larsen said. "It's a question of timing. When can we take it out and use it? It can move to the Ranney wells and move back into the ponds."
Runyan asked if water could be retrieved from Bill Evans Lake. Larsen had no answer.
Domenici asked if a 35-acre pond and one Ranney well in Virden would have comparable costs, and Larsen said: "Yes."
Larsen said each ditch can handle 20 cfs conveyed.
Domenici commented that the AWSA construction fund has between $52 million and $55 million, indexed. "You have only two phases in that range."
Larsen said the alternatives are designed to 3,000 acre-feet per year. "They can all be designed to meet a diversion rate of 150 cubic feet a second or 50 cfs"
Domenici asked: "In most years, are we going to be able to fill and refill the ponds until the water is needed?"
Larsen said surface storage is close to 100 percent reliable to provide water. "This is all fairly high level and includes operations and maintenance costs."
Hutchinson said looking at the various alternatives, he calculated $213.6 million for San Francisco full build out. "When I look at the figures and the consumptive use of 2,900 acre-feet, is the life expectancy about 30 years?"
Larsen said a project could be designed to last a longer time or a shorter time. "It changes costs."
Hutchinson said the project was looking at 48-inch pipe from Spurgeon Reservoir." If we use a lower cfs, could it be smaller?"
Larsen said a 48-inch pipe makes it easier to maintain and get rid of silt.
Hutchinson noted that even at $245 per acre-foot with 2,900 acre-feet, "with my back-of-envelope calculations, it seems like fairly cheap water."
Sikora said the cost of diversion is location, location, location. "Your next decision will be what kind of diversion you want."
Larsen said for dams and reservoirs, location and geology, each one is unique.
Hutchinson said he would feel more comfortable getting more detail, such as whether the material could be from the site or require transportation.
Runyan said it looked like 50 cfs would allow the users to divert more days a year.
Larsen said the ponds can also be used for adjudicated water to build a head for irrigation. "You don't have to restrict how you use the ponds."
Kim Abeyta-Martinez, the non-voting member representing the Interstate Stream Commission, asked where the 210-acre pond would be.
"We have not identified it by ownership," Larsen said. "It was identified by aerial photography."
Runyan said the Gila Farm Ditch has 10 users. "In July, we would be taking water 24/7. Right now, no one is taking water. That's why the shoulder months are intriguing for other crops."
Campbell persisted saying that Mogollon seems logical.
Hutchinson asked Domenici. "If we are looking at phased construction, it's $44 million. If we put into place a diversion structure to allow ASR and for on-farm ponds, would these designs be what would go through NEPA?"
Domenici said he would draft a letter to the Bureau of Reclamation. "Cost caps could be part of it. We need to put something like alternative 6, and leave the yellow on the map to determine whether it would be realistic within five to 10 years to complete the NEPA. I think the green bullets might be more realistic. I am committed to cost caps. I think otherwise, the NEPA would likely be stale by the time we want to expand the phases." He was referring to the maps for Alternative 6 on page 26.
Hutchinson said: "If we don't include some reservoirs and NEPA goes forward, it doesn't preclude reservoirs later."
Domenici agreed, but said NEPA would have to be done on the areas for the reservoirs if not done this time around.
"What is essential for NEPA is what we intend to divert for direct use and/or for storage," he said. "The AWSA water for direct use and storage have to be in NEPA."
"Does the Secretary (of the Interior) have to issue a record of decision just on what we do this time?" Hutchinson asked. "What if there is a second phase? Are we precluded from doing more beyond that date?"
Domenci said: "The construction money will be exhausted. There will be New Mexico Unit Fund dollars, but still, under statute, controlled by the ISC. We would probably need an amendment to the JPA for design and construction. Where that money goes is largely up to the ISC. The cap on the construction fund is $62 million, with it right now at $52 million to $55 million."
The rest of the meeting will be covered in the next article.
Larsen asked for board members to contact them for more questions.