Editor's Note: This article completes coverage of the more than two-hour Interstate Stream Commission public meeting on the Arizona Water Settlements Act planning process held on July 21 and includes the presentation on the third diversion and storage proposal, as well as questions and answers.
By Mary Alice Murphy
Jeff Riley, Bureau of Reclamation Phoenix office chief, design and construction branch, presented an overview of the third diversion-and-storage proposal that was part of the Tier-2 planning process, as well as presenting other options.
The Hidalgo County Off-Stream Project has the three principal components of diversion, open channel conveyance and two storage reservoirs. The water would be gravity flow to Schoolhouse Canyon by 35 miles of open channel. Schoolhouse could store 2,000 acre-feet.
The diversion would take water upstream. "There have been discussions on the problems of sedimentation," Riley said. "The solutions may not be inexpensive, but there are solutions, such as settlement basins and inverted siphons. The canal carries 350 cfs in a 24-foot wide surface, which could include concrete-lined canals."
The total project cost is estimated at $235 million, with OM&R at $1.5 million a year.
"What about the footprint?" a man asked.
"The footprint would be 70-80 feet, depending on the slope of the land," Riley replied. "A small storage at Virden would hold 57 acre-feet of water and can be fed by an existing diversion."
Other diversion-and-storage options determined by Reclamation include four diversion locations, 24 storage locations, with seven locations selected for further analyses and three storage multiple-canyon configurations presented.
Diversion point 1 by the stream gauge would not require a conveyance structure in the steep-walled canyon. It would have four potential storage sites, Winn Canyon, which could hold 2,760 acre-feet in a 109-acre reservoir; Pope Canyon with a storage capacity of 7,900 af, in a 219-acre reservoir; Sycamore Canyon, with a capacity of 36,900 af in a reservoir of 583 acres; and Greenwood Canyon to store 26,000 af in 481 acres.
Diversion point 2 has a diversion at Turkey Creek and points 3 and 4 are at the mouth of Turkey Creek. "You can get more into storage from a higher elevation," Riley explained.
Diversion point 2 has one storage site—Dam Canyon, which can hold 9,400 af on 135 acres.
Diversion 3 also has one storage site—Garcia Canyon, which can store 7,500 af on 203 acres of reservoir.
Diversion 4 would store water in Spar Canyon, with a capacity of 9,400 af on 135 acres.
Riley said the Greenwood Canyon storage option would require moving three miles of highway 180 and two miles of NM 211. The cost includes the rerouting.
He also presented three alternatives, which are multiple-canyon storage options.
Alternative 1 would hold 64,000 af in Sycamore and Greenwood canyons for a cost of $598.5 million and OM&R of $4.5 million. Alternative 2, with storage of 10,600 af in Spar and Garcia, would cost $294 million, with OM&R of $2.5 million annually. Alternative 3, with storage of 14, 250 af in Mogollon and Winn canyons would cost $307 million, with OM&R of $2.7 million a year.
The cost per acre-foot of water in Alternate 1 would be the most-cost effective, because of the greater storage capacity, Riley said.
"This is a typical embankment dam configuration, with zone 1 being an impermeable core," Riley showed a conceptual drawing of the dam type. "Miscellaneous considerations would be replacing diversion with infiltration galleries, but the cost is twice as much below ground."
Riley said the water treatment at Deming would be about $21.2 million for 3,900 af going to Deming.
"Another possibility is a tunnel versus an open channel, with a tunnel possibly saving some money," Riley said about the options and alternatives. "Lining reservoirs would cost $163,000 for a 2-acre pond and would cost $9.1 million to line Winn Canyon.
"I heard a sentence about 12,000 acre-feet being the safe water yield," a man said. "The statistics on evaporation rates show that a reservoir would lose 5,000 acre-feet, leaving 7,000 acre-feet delivered to users. We're not talking about 14,000 acre-feet."
Another man said he was a botanist and "I see major flaws. I don't see anything about keystone species. Also with a lot of water surface you bring dengue fever, West Nile virus, serious pathogens. There is nothing about trees. This region has the highest percentage of native trees in the West. We won't have that many with changes. We have a democracy and this project is not wanted. Stewart Udall told me he was sorry he voted for the Central Arizona Project."
"How much for the one system for storing 64,000 acre feet?" a man asked.
"$600 million," Riley replied.
The same man protested: "More like $750 million to $800 million. I didn't see the OM&R and the exchange costs aren't there.
"We're taking them (exchange costs) into consideration in the economic analyses and will consider adding them to the O & M," Riley said. He added: "It's possible you can pump directly from the alluvial source."
The same man asked about electrical costs, to which Riley replied that they are all broken out in the full report.
A woman urged Reclamation to add the CAP costs to the O&M. "You have to look at total costs so you can reflect all values."
Another woman asked if reservoirs would be open for recreation and what impact they would cause.
Steve Piper, Reclamation economist, said he assumed some recreation in the analysis of benefits.
"Did you consider putting the water into Snow Lake and letting it come down the river?" one man asked.
"We started working with the Tier-2 proposals from local entities," Riley said.
"How much actual water will be gotten from these projects?" a woman asked.
A man pointed out that the Conner Dam cost benefit analysis had very poor cost benefits. "These analyses maybe have even poorer cost benefit."
"In calculating benefits, we look at face value for municipal and industrial use and agricultural use," Piper explained. "The quantity of water appraisal study is done with available information. We used studies and then simple recreational values for benefits. On the costs side, diversion costs have gone up from what I used. All the present value is for 50 years. We did show the negative benefits if it goes forward. Reclamation will do a much more rigorous study. This is appraisal level and a rough estimate."
"The cost benefit analyses? In your experience, is this normal for projects that get implemented?" a man asked.
"The driver is the cost of the project, so in some way it is typical with construction costs and exchange costs taking away some of the benefits," Piper replied.
"The numbers for the economic analyses don't include evaporation and other costs," a man said. "Will the economics be revised?"
"The costs are dependent on so many things," Riley said. "A 1,000 acre-foot reservoir can fill every year. If it's a 12,000 or 14,000 acre-foot reservoir, you can get into evaporation losses. At this level, there are too many unknowns. We don't know the final uses; we don't know the geology; we cannot put hard numbers, because we don't have the information."
"I presume these studies were done before the earthquakes," a woman said.
"I would have been disappointed if no one had mentioned the earthquakes," Riley said, laughing. "Dams nowadays are built to withstand seismic activity in the region."
"Would there be recreation opportunities?" a man asked.
Riley said there would be serious limitations.
"You are approaching $1 billion dollars, if you build in cost overruns," a man said. "Is there any look at the fiscal ability to pay for this?"
"There is one page in the report talking about the financial feasibility," Piper said. "We have to know what is reimbursable and what can be paid for by M&I. We don't know the purposes or what financial arrangements can be made."
"Is there a comparison to non-diversion alternatives?" a woman asked.
"We were only tasked with diversion and storage," Riley said. "We won't endorse anything. This is just information for decision-making."
"What about climate change and the 14,000 acre-feet?" a woman asked.
"There is a question whether New Mexico can meet the downstream CUFA limitations," Riley said.
The same female said he estimates for the amount of water are going down.
"The thought has been given to us," Riley said. "We were just asked to evaluate the diversion-and-storage proposals. I'm not going to address climate change."
"There have been studies on the non-diversion alternatives," David Anderson, ISC Water Resource Specialist Senior, answered an earlier question. "We've given other presentations on non-diversion projects. All the studies are at nmawsa.org."