Editor's Note: This article covers the last two sessions of the Sixth Annual Natural History of the Gila Symposium.

By Mary Alice Murphy

The presentation phase of the Sixth Natural History of the Gila Symposium was held Thursday and Friday, Feb. 25-26 at Western New Mexico University. The last presentations included four on the Arizona Water Settlements Act of 2004 and its planning and processes.

Norman Gaume, engineer and former Interstate Stream Commission director, gave the third presentation titled: Scientific Simulation of the Water Yield of the New Mexico Unit of the Central Arizona Project.

"I have a different take from the previous speaker," Gaume began. "I have done a detailed analysis of the yield that can be expected from a diversion. A graphic in the Reclamation value study paints a clear picture of the difficulties that lie ahead."

 

He said the AWSA is the fourth incarnation of the Colorado River Basin Project, proposed in 1968 with authorization to build a structure on the Gila River. "It would divert junior rights water that would otherwise go to San Carlos Reservoir and it would be replaced by water from Lake Havasu."

Gaume said rarely would there be enough water in the Gila River to fulfill the AWSA allocation.

"As of today, there is no physical incarnation of a diversion," he said. "What is the water yield? What is the risk? It's an incredible stretch to say that best available science has been used. Off stream storage will be required."

He said he hired Peter Coha, "the best Excel and graphics guy I know," and Jim Brainerd, a retired hydrologist and author of the Sandia Labs Model, which was never formally released, to analyze the diversion yield that would be legally available. "That's different from usable, because of water evaporation and inefficiencies of the system."

Gaume said junior water rights are rarely available on an over-appropriated river system. John Fleck in his blog said on Feb. 18. 2016: "It 'sucks' to be junior..."

"The ISC model by Sandia Labs was abandoned because it did not show enough water available," Gaume alleged.

He showed several charts showing mean and median flows with 79 daily points for 79 years. "Because of bypass requirements of the Consumptive Use and Forbearance Act (an addendum to the AWSA), the mean has a little bit of water available, but the median none."

Gaume said the water available consisted of snowmelt and a little bit during the monsoon season. Eighty percent of the water available occurs between January and April. "With climate change, the prediction is that snowmelt will be gone, so that's a huge uncertainty. Just because there's a lot of water in the Gila doesn't mean it is legally divertible."

With a mean flow of 12,600 acre-feet, and a median of 3,900 acre-feet, "more than half the years, there is little to no water available. Brainerd's reservoir storage volume simulated usable water of 5,400 acre-feet a year. That's a far cry from 14,000 acre-feet."

He gave some insights on the record back to 1937. "In the 1980s and 1900s, we had the wettest years out of the past 1,000 years. That biases the record and the distribution is skewed. Water is rarely available, and none is available during drought. The mean is less than the magnitude of the junior water right. It requires efficient storage, which will only happen if the reservoir is lined. That's expensive."

Gaume said he thought the yield of 5,400 acre-feet a year is "an unachievable maximum. There will be required mitigation for species. How much water is there for whom? At what cost and paid for by whom?"

He also questioned the best available science and said: "No, it was the best paid advocates. What makes ISC's dedication to this junior Gila/AWSA water rational?"

Craig Roepke, Gila Project manager, said he was not going to try to tell participants the yield, "because we don't have the necessary parameters. We didn't publish our results because we would do them only on concept, with one exception. We hired nine professional engineers and tasked them to estimate the yield at that time. They said between 7,000 acre-feet a year and 9,000 acre-feet a year, if we had a big reservoir."

"No one is intending to do a 64,000 acre-foot reservoir nor a two-and-a-half mile tunnel," Roepke said.

"We tried to create something that the public could fool around with," he continued. "The model contains the parameters necessary to illustrate impacts. The validity of the model and parameter values is easily verified. The ISC used much of the model by The Nature Conservancy and the TNC drought calculators.

"Norm calls this a diversion yield model," Roepke said. "The models by Norm and ours are not that different. We linked our diversion model with what we call a yield model. You can take our model and modify it. We do not refer to mean or median, but it's a calculation of historical data. We linked possible climate change with the actual historical data."

He said Bill Evans Lake has a measured seepage of 38 percent. "If we line the reservoir, it will cut seepage. A lot of people are concerned that flows in March are critical."

"Someone said you can change the model until you get the 'right answer.'" Roepke said. "That's exactly right. This is a tool that is entirely transparent. You can look at every cell to see the calculation."

He explained the Consumptive Use and Forbearance Agreement. "The consumption happens in New Mexico. The forbearance is by those downstream. They forbear from calling for senior water rights, if we stay within the parameters of the CUFA."

Helen Sobien, ISC engineer, gave thefinal presentation. "These are the municipal water conservation projects the ISC voted to fund in December 2015."

She gave the questions to be addressed:
G

Content on the Beat

WARNING: All articles and photos with a byline or photo credit are copyrighted to the author or photographer. You may not use any information found within the articles without asking permission AND giving attribution to the source. Photos can be requested and may incur a nominal fee for use personally or commercially.

Disclaimer: If you find errors in articles not written by the Beat team but sent to us from other content providers, please contact the writer, not the Beat. For example, obituaries are always provided by the funeral home or a family member. We can fix errors, but please give details on where the error is so we can find it. News releases from government and non-profit entities are posted generally without change, except for legal notices, which incur a small charge.

NOTE: If an article does not have a byline, it was written by someone not affiliated with the Beat and then sent to the Beat for posting.

Images: We have received complaints about large images blocking parts of other articles. If you encounter this problem, click on the title of the article you want to read and it will take you to that article's page, which shows only that article without any intruders. 

New Columnists: The Beat continues to bring you new columnists. And check out the old faithfuls who continue to provide content.

Newsletter: If you opt in to the Join GCB Three Times Weekly Updates option above this to the right, you will be subscribed to email notifications with links to recently posted articles.

Submitting to the Beat

Those new to providing news releases to the Beat are asked to please check out submission guidelines at https://www.grantcountybeat.com/about/submissions. They are for your information to make life easier on the readers, as well as for the editor.

Advertising: Don't forget to tell advertisers that you saw their ads on the Beat.

Classifieds: We have changed Classifieds to a simpler option. Check periodically to see if any new ones have popped up. Send your information to editor@grantcountybeat.com and we will post it as soon as we can. Instructions and prices are on the page.

Editor's Notes

It has come to this editor's attention that people are sending information to the Grant County Beat Facebook page. Please be aware that the editor does not regularly monitor the page. If you have items you want to send to the editor, please send them to editor@grantcountybeat.com. Thanks!

Here for YOU: Consider the Beat your DAILY newspaper for up-to-date information about Grant County. It's at your fingertips! One Click to Local News. Thanks for your support for and your readership of Grant County's online news source—www.grantcountybeat.com

Feel free to notify editor@grantcountybeat.com if you notice any technical problems on the site. Your convenience is my desire for the Beat.  The Beat totally appreciates its readers and subscribers!  

Compliance: Because you are an esteemed member of The Grant County Beat readership, be assured that we at the Beat continue to do everything we can to be in full compliance with GDPR and pertinent US law, so that the information you have chosen to give to us cannot be compromised.