The Gila/San Francisco Water Commission at its meeting Tuesday, May 21, in Deming heard two presentations—one from Martha Cooper of The Nature Conservancy and another from Craig Roepke, Interstate Stream Commission deputy director.
At the beginning of the meeting two items were added to the agenda—a discussion on a proposed brochure and a communications committee report.
Martha Cooper of The Nature Conservancy said the organization received from the Desert Landscape Conservation Coalition funding to look at flow-ecology relationships. She cited a recent presentation by Deborah Hathaway of Papadopolus & Associates, which showed little impact on the ecology from flow changes, except in late winter and early spring. "She made clear one piece of the impacts. The purpose of our project is to synthesize and give our information to agencies."
Cooper said the background report would focus on the existing condition as a baseline. "When I gave this overview to the Gila Basin Irrigation Commission, Topper Thorpe said that agriculture wasn't mentioned, but it is included," Cooper said. "We are analyzing four reaches where there are groundwater monitors in a 20-mile stretch from the Gila Gauge to the Bird Area."
The project will include flood history, geomorphology, riparian vegetation, wildlife and hydrology. "We will have two scenarios. One is similar to Hathway's, and the second will include climate change projections working with the University of Arizona and the University of New Mexico, including various scenarios with a link to water, not just weather."
The scope of the project will include surface water inundations and how they affect groundwater. "Small flood events cause infiltration into the groundwater. We want to know how long the infiltration lasts."
To a question, she replied the monitored wells are along the main stem of the Gila River in the floodplain.
"We are looking at how vegetation could potentially change," Cooper said, "as well as aquatic and amphibian species."
Two experts, Tim Turner and Dave Propst, will provide a new synthesis of 25 years of data. One section of the study will be on riparian obligate wildlife, including birds.
"After the chapters are written, there will be a workshop where experts come together and come to agreement on the flow patterns and the ecosystem we have now," Cooper said. "Components can be done by rigorous scientific study, such as the distance of cottonwood roots to groundwater. The validity of the study will be because people agree to it. We will try to accurately reflect the conversation and then create the final report." The experts come from the University of Arizona, University of New Mexico and one from Kansas.
The workshop will be held in January and the final report will be available in April, followed by outreach.
Anthony Gutierrez. Grant County GSFWC representative, said: "I am assuming there will be data. I know a section of the river below the Freeport McMoRan diversion where there are no trees. Most of the river has riparian areas alongside. I've always wondered why this stretch has no trees. The only trees are where a fence was built and the poles grew."
Cooper said the study would be on only four reaches, where the groundwater monitors are. "I imagine the lack of trees is linked to the diversion."
GSFWC member Javier Diaz, representing Luna County, suggested it might be because the soil is tight sandstone without much clay.
M.H. "Dutch" Salmon of the Gila Conservation Coalition asked Cooper about the several diversion proposals that are under study by the ISC. "What kind of assumptions are you making about where they are and the engineering plans?"
Cooper said the study has presumed the diversion will be at the top of the Gila Valley. "If a preferred diversion appears, we will adjust the study."
To a question, she said the grant was for $105,000, with a match from The Nature Conservancy of $105,000 from donors and organization funds.
"I have been asked if all the water that the Arizona Water Settlements Act allocates (14,000 average annual acre-feet) will be taken at high floods," Bates said. "Are you looking at large floods?"
Cooper said the study would look at all floods, although the most frequent are the smaller floods. "Hathaway suggested there would be no impact with diversions, but we're looking at that. We are using the same Consumptive Use and Forbearance Agreement parameters for withdrawing water."
About eight scientists are on the study's core team, Cooper said, and about 50 have been invited to the workshop. "The workshop will be a work session, not for public education."
Alex Thal, GSFWC member representing the Grant Soil and Water Conservation District asked if The Nature Conservancy planned to get input from the Gila/San Francisco Water Commission.
"We will take input," Cooper said.
"I request that the New Mexico State University Water Resources Research Institute do a peer review of this study and its methodology," Thal said.
"We will provide the draft for public comment," Cooper said. "We would welcome WRRI review." She said she would email the link to the proposal to Thal for distribution to the soil and water conservation districts and the GSFWC.
Roepke asked for clarification on the two scenarios proposed in the study. Cooper said one would be a diversion based on CUFA parameters and the second scenario would be on the effects of climate change. "We will also look at a combination of the two."
"I was told that two people from the ISC would be working on the study," Roepke said.
"We're sharing the groundwater wells data with Hathaway," Cooper said.
"What background is the ISC allowed to offer?" Roepke asked.
"Just like any other agencies," Cooper replied.
Because the item on peer review was not on the agenda as an action item, GSFWC member Vance Lee, representing Hidalgo County, asked that it be on next month's agenda.
Thal said he would talk to the WRRI about the peer review, "because there should be an independent peer review outside the process."
Roepke then prepared to give his presentation, which will be covered in a future article.