Editor's Note: This is part 2 of the Interstate Stream Commission quarterly public meeting on the Arizona Water Settlements Act. This report addresses some of the history of the Bureau of Reclamation's part in the process, as well as a report on two of the diversion projects. The other diversion will be covered in the final article, which will also include the question-and-answer period.
By Mary Alice Murphy
Vivian Gonzales, Bureau of Reclamation water resources planner, continued the presentations at the Interstate Stream Commission quarterly public meeting to update people on the studies being done as part of the Arizona Water Settlements Act planning process.
"Reclamation completed its draft report on the AWSA Tier-2 diversion projects," Gonzales said. "This evening, we will not review the entire report, but just the engineering assessments."
For a little history, she said, the role of Reclamation is to provide oversight for the Secretary of the Interior and manage the Lower Colorado River Basin Development Fund, as well as assure environmental compliance of a New Mexico Unit.
The 2004 Arizona Water Settlements Act Modified Central Arizona Project Upper Gila Exchange Requirements include that New Mexico must decide whether to construct a New Mexico Unit and notify the Secretary by Dec. 31, 2014. New Mexico can exchange up to an annual average of 14,000 acre-feet from the Gila and San Francisco rivers. Funding allocated by the AWSA is divided into portions, with $66 million to be transferred to New Mexico to pay the costs of the unit or other water utilization alternatives.
To date, as the money is indexed, the state has received three $9 million allocations out of the ten annual payments that will be sent to the state. That is a total of about $27 million. An additional $62 million is available if New Mexico chooses to build a unit for the exchange.
Reclamation signed a memorandum of understanding with the Interstate Stream Commission on May 7, 2013, to do appraisal-level work on engineering assessment of the three Tier-2 diversion and storage proposals; identification and engineering assessment of other diversion and storage options; economic analyses of Tier-2 proposals and other diversion and storage options; environmental review for potential effects of diversion and storage proposals, and issue a final report to the ISC by July 31, 2014.
Fifteen Tier 2 proposals, of which three are diversion and storage, have been analyzed.
An Audubon Society representative asked: "Why are the economic analyses not presented?"
"The ISC asked us to present the engineering assessments, but the economic analyses can be found in the report at nmawsa.org under ongoing-work," Gonzales said.
"What's happening to the $27 million?" a man asked.
Gonzales explained the funding could be used for a unit or other alternatives.
A female speaker asked: "The $27 million hasn't been spent? Isn't it part of the payment process?"
Gonzales said the funding is part of the payment process. Some of the funding has gone to pay for the studies.
She introduced Jeff Riley, Reclamation chief, design and construction engineering branch.
"We divided the diversion and storage proposals into single canyon and multiple canyon options," Riley said. "A maximum of 64,000 acre-feet of water can be diverted in a single year, with a total of 140,000 acre-feet over a 10-year period. The amount of 10,000 acre-feet is just for the Gila allocation of the annual average 14,000 acre-feet."
The three Tier-2 diversion and storage proposals are the Gila Basin Irrigation Commission proposal; the Southwest New Mexico Regional Water Supply Project, also known as the Deming pipeline and the Hidalgo County off-stream storage proposal.
The other alternatives Riley discussed require no pumping, but are all gravity flow from storage.
The engineering assessments include how the water could be diverted and stored and the cost estimates.
"Some economic estimate and cost estimates in the report don't match, but we will resolve them," Riley said.
The GBIC project has diversion, open channel conveyance and underground storage components. Two diversion structures would be located at the confluence of Mogollon Creek and the Gila River, replacing the existing Upper Gila Ditch and the Fort West diversions, and a second structure at the existing Gila Farms diversion location.
The functional structures would be 500-600 feet across, with a concrete diversion structure and gates. An additional 350 feet would be wing walls to prevent erosion.
"How high will it be?" a man asked.
"We would have to bump the water up six feet to get the flows," Riley said.
"How much water will be stored?" another man asked.
"I will get to answers to both questions," Riley said.
A female asked: "Who owns the land?"
Riley said he thought it might be private. "A map in the report will show whether it is Nature Conservancy property."
"We would connect the diversion structure to existing canals," Riley resumed his report. "It is unknown how much the capacity for the canals is and whether the storage would be in the alluvium or above ground. The canals would carry 350 cubic feet per second."
"How far back will it pond?" a woman asked.
"At six feet deep, about 1,000 feet upstream," Riley replied. "It will sediment in and cause channel braiding. We will push water up to get to the gates, six feet above the present invert of the channel."
He said the GBIC lower diversion would be in a wider part of the floodplain.
"Farther downstream, so there are two dams? High ones?" a man asked.
"Yes, there will be two, but neither is designed yet, so we don't know how high the structures will be," Riley replied.
Moderator Tom Bates asked that audience members "make your questions pertinent to what he is saying."
"The downstream dam would require wider boom walls," Riley said. "Storage would be in in infiltration gallery, with a recharge system or a collection system, with intervals of 10 feet and lots of pipe; on-farm storage ponds: and/or injection/pumping wells. The more cost-effective are discussed in the report."
The injections into the alluvium would be about 18-feet deep to store 500-1,000 acre-feet. The recharge system would be buried to four feet, below the plowing zone.
"A conceptual collection system is not as intrusive as the recharge system," he said. "The lower project can discharge 12 cfs into the river into the Gila Farms diversion.
"The GBIC on-farm open ponds would store about 30 acre-feet of water altogether on the proposed 10 ponds, but with a lot of seepage losses," Riley said. "Lining a pond would cost about $160,000 each or they could be used recharge basins.
"The total cost estimates for all of the components is $41.8 million, with operations, maintenance and replacement, at 1.4 percent of the total project cost, would be about $585,000 a year," he continued.
"Evaporation in the ponds is not accounted for, and some water in the collection system would be unrecoverable," Riley said.
"How many farms are served by the river? Are there any commercial farms or are they hobby farms?" a female speaker asked.
A man asked: "What's it going to look like and are you getting information on the dollars?"
"There is a way to design them, so that they won't affect the farm fields," Riley replied. "There will not be much impact visually."
"What changes will they cause to land use?" the same male speaker asked.
"I don't see any changes," Riley said. "The use is primarily agricultural. The thought is to store water in the ground to divert it into the river and then users can divert at the existing Gila River diversions. There will be some sort of structure, with some concrete and wing walls."
A man opined that 30,000 cfs flow would erode a structure.
"What is the size of the canals?" a female asked.
"They can take 350 cfs at a time, if you are only putting the water into the recharge systems," Riley said. "The canals won't look any different from now."
"Has the GBIC determined how much it will be per acre-foot?" a woman asked.
"The AWSA water has to be replaced by the Central Arizona Project to make whole those downstream," Riley explained. "The water price per acre-foot is the CAP water exchange costs, which is about $140 right now."
A man said and asked: "It's a small amount of storage. What about the economic analysis?"
Riley replied that the information could be found in the report.
"The city of Deming proposal has as principal components, diversion, storage reservoirs and closed conduit (pipeline) conveyance," Riley introduced the next proposal.
"What will Deming use the water for?" a man asked.
"That is not in the proposal, but presumably for municipal use," Riley replied.
"The Mogollon Creek dam would store 5,000 acre-feet," he continued from the presentation. "Subsurface collection would go from the alluvium into the Mangas Creek dam. All dams are earth fill, embankment dams. There will be a cutoff wall below the dam to bedrock. We know the depth of the alluvium to bedrock for five potential sites, but there is a massive lack of information on the geology. The Mangas structure would store 30,000 acre-feet, from which the pipeline to Deming would be 73 miles."
Riley explained that five pumping stations would get the water over the Continental Divide, and then it would be gravity flow to Deming. "So much pressure would build up that electricity could be generated."
The total cost of all components would be $503 million, with OM & R to cost about $8.85 million a year.
"What about endangered species? Mitigation is not included," a man asked.
Kim Musser, Reclamation environmental specialist, replied. "Mitigation would be required with consultation of U.S. Fish and Wildlife Service giving suggestions for mitigation. No project is chosen yet, so the process has not started. It will add substantially to the cost."
The next article will conclude the meeting.