Editor's Note: This is the first of several articles covering the ISC quarterly AWSA public meeting held June 21 and includes four presentations and the questions and answers that followed them.
By Mary Alice Murphy
Tom Bates of Silver City served as moderator for the Interstate Stream Commission's quarterly Arizona Water Settlements Act public meeting held in the Cliff School gym on Monday evening, July 21, 2014.
David Anderson, ISC Water Resource Specialist Senior presented the first three presentations, the first of which was Analyses of flow and water use alternatives on hydrologic changes in the Cliff-Gila Valley, a study by SS Papadopolus.
"It studies the surface and groundwater interaction hydrologic changes, as a result of an AWSA diversion," Anderson said. "The 3-year calibration was matching simulated water levels to observed water levels and was completed in 2014."
He showed a map of where piezometers were placed.
The study addressed four scenarios:
Scenario 1: A low flow year with a low AWSA diversion, which showed a water year with a flow of 77,167 acre-feet of water and a diversion of 5,008 acre-feet, in March and early April. The groundwater level declines of ¼ to 1 foot were less as one moved downstream. After cessation of the diversion, the water level recovered within one week.
Scenario 2: A long-term mean annual flow with a high AWSA diversion indicated flows of 102,025 acre-feet by April 1 of the water year, which began Oct. 1. The diversion was 13,091 acre-feet. The groundwater level declined by ¼ to 1 foot and the recovery, after diversion cessation, was one to two weeks.
Scenario 3: A high-flow year with a high diversion, followed by a drought year. The scenario spans two water years and would have a diversion of 21,025 by April 1 of Year one and no diversion during Year two. The groundwater level would decline from ¼ to 1 foot and, upon diversion cessation, recover within less than one week.
Scenario 4: A high flow year with a high AWSA diversion followed by a drought year would yield a flow of 69,828 acre-feet and for Year two, 38,559 af flow. A diversion of 5,653 in early August of Year one and no diversion during Year two would bring a groundwater decline of ¼ to 1 foot, which would recover quickly.
"All presentations are posted on nmawsa.org under the ongoing-work tab," Anderson said.
A female from the audience asked: "Who makes the decisions on subsequent diversions?"
"The allowed diversions are outlined in the Consumptive Use and Forbearance Act, which has the legal constraints of how much water can be taken when," Anderson replied. "It's a function of about 10 different things."
"For the study was the water diverted or was it hypothetical?" a man asked.
"We have historic data and several piezometers that measure groundwater elevations," Anderson said. "The historic data was calibrated against the piezometer data."
"What years?" the same man asked.
It was overall historic data, but actual years were modeled, Anderson said. To the man's question about the most recent year, Anderson said he thought it was 2011.
"But you didn't account for future flows and declines in flows from climate change?" the man asked.
Anderson reiterated that it was based on historic data. "I asked how difficult it would be to use climate change in the model. I was told that I could just look at the low flow years."
A Silver City woman pointed out that in the 1950s, it was dry and the 1980s had high precipitation. "Did the model look at spans of years or is it an overall average?"
"It's not an average, but actual years," Anderson replied. "We looked for data to match the chosen scenarios."
The second presentation was Modeling Benthic Macroinvertebrate responses to proposed diversions, with the study done by HDR Engineering Inc.
"The study was on insectivores," Anderson said. "We were interested in the fish and birds that rely on certain insects. The study looked at fish habitat, but didn't consider whether there was food for the fish."
The study was to develop the BMI flow-ecology relationships and predict BMI productivity.
"We did field sampling and hydraulic modeling and sent samples to the same lab the New Mexico Environment Department uses," Anderson continued. "We will report on two sites out of 8 for subaqueous substrates."
Site 8 is just below Turkey Creek. Sites 7 and 8 were control sites.
He showed a graph of the results.
"Site 5 is below the Fort West Ditch," Anderson said. "Where the graph plunges to zero on the Y-axis is where the channel dries in late May and early June. The model shows a five-day dessication and a 47-day lag to recovery of the insects. After a diversion, productivity decreases slightly—by about a half of 1 percent."
"Site 5 compares productivity where it goes to zero compared to if water is released from storage," Anderson continued. "Releases ranged from 10 cfs to 40 cfs. With any of those releases, we don't see the productivity go back to zero. With increased flows, you get greater wetted areas, but the greatest increase of productivity is at 10 cfs."
"How is the .5 percent calculated?" a man asked.
"For the entire reach of the river," Anderson clarified. "A water year is from Oct. 1 of one year to Sept. 30 of the next year."
"Does the data of macroinvertebrates include non-natives, such as crayfish?" another man asked.
"We did sample crayfish," Anderson said. "I'm not sure if they were the native or the non-native. The sampling for the BMI metrics didn't include that the NMED doesn't have biomass data."
"You said Site 8 was the control?" an audience member asked.
"Yes, because there are no diversions at Turkey Creek and Mogollon Creek," Anderson replied.
"You said there was a loss of one half percent of productivity," an earlier female speaker asked. "Was there any study on the consumers of the food chain—the fish and the birds?"
"The study didn't look at those relationships," Anderson said. "It looked at spikedace and loach minnow studies.
"This gives a good idea about what happens when the channel dries, with a five-day dessication and 47 days for recovery when the channel is rewetted," he said. "The fish can come back sooner, but maybe they will have nothing to eat."
"Is the half a percent significant?" a woman asked.
"No, because AWSA diversions are predicated on high flows for a short time," Anderson replied. "Floods are not macroinvertebrate habitat. There is a ceiling where productivity maxes out."
"Is the .5 percent included in the control?" a man asked. "And did you account for changes in water temperatures?"
"Yes, the half a percent was included in the hypothetical flows from storage," Anderson said. "We don't have that information on temperatures. We only accounted for wetted areas, not temperatures."
The third presentation by Anderson was on the completion of the municipal conservation pilot programs.
In February 2012, the ISC allocated $100,000 for pilot projects in Deming and Silver City.
Deming's water development plan indicates that 49 percent of water productivity is used by the residential sector. The difference between January and June water usage is 153 acre-feet. An acre-foot is about 136,000 gallons.
Two rebates were offered—one for $1 a square foot to replace turf grass with xeriscaping; the second was a $1,000 rebate to change from a swamp cooler to refrigerated air. The town met with local landscape contractors and with HVAC contractors. The town advertised in newspapers and partnered with PNM to get the word out.
Two landscapes were changed to xeriscape, for about 1,210 square feet. Eight swamp coolers were replaced with refrigerated air. Sixteen percent of the grant was expended.
Anderson said several lessons were learned:
•The town needs to get with the community first to find out what the community wants to do. Focus groups would meet that requirement.
• The program must reflect the local economy—replacing a swamp cooler may cost up to $10,000, so $1,000 is not enough.
• Partner with other programs and agencies.
Deming does have a strong conservation effluent reuse program, irrigating turfed areas with treated effluent.
The Silver City pilot program was developed by D.B. Stephens & Associates. The Altamirano Sports Complex was the top single water user, with 11.5 acres of cool-season turf grass. D.B. Stephens thought the town could save 24 acre-feet of water.
A weather-based irrigation system was installed, as well as new rotors that were higher efficiency, and leaking sprinklers were replaced.
The town has not received the water audit, due in August.
Savings were determined to be 19 percent to 39 percent, out of 2.5 percent of Silver City's total usage.
"Did Silver City spend all the money?" a man asked. "What happens to the balance of funds?"
"Silver City spent $49,751," Anderson replied "The funding came out of the New Mexico Unit Fund."
"Is the Altamirano Complex in the town? Where's the boundary line?" an audience participant asked.
"The complex is operated by the schools and the water comes from the Silver City water system," Anderson said.
"On a daily basis, how many gallons of water does a swamp cooler use?" a man asked.
Another man answered: "I put a water meter on my swamp cooler and it uses about 50 gallons a day."
"While the next presenter is getting ready, I would like to ask for a moment of silence for the three Aldo Leopold Charter School students and the doctor pilot who died in the plane crash, as well as for the Signal Peak lookout who died in a horseback-riding accident," Bates requested.
Ali Effati, ISC civil and water resources engineer, presented the technical review by RJH Consultants Inc. of Bohannon-Huston's draft final preliminary engineering report of a diversion.
"The reason the ISC chose RJH was because the firm has experience on small dams and is licensed in New Mexico," Effati said. "The scope of work was to identify any significant issues and provide recommendations for improvement."
He cited the strengths of the PER as an appropriate level of investigation and data collection and analyses for the appraisal level.
Weaknesses included inadequate addressing of some components, such as dam site geology, AWSA water yield and sedimentation.
Effati said the review showed there was a high potential for seepage loss. The AWSA water yield had no mention of timing. The Gila River carries a high quantity of fine sediment particles, especially during high flows.
Minor issues included river crossings, irrigation diversion structures and storm water detention facilities.
Recommendations included documenting the water yield and performing additional geotechnical studies.
"I'm not alone in my concern about the BHI cost estimates," a man said. "What will happen with these deficiencies?"
"We have already put all the recommendations into a work order to BHI and all have been included," Effati said.
"When will they be included in the report?" the same man asked.
When Effati replied that it would be done by mid-September, a woman protested it was not in time for the ISC preliminary decisions.
"I'm not sure when the decisions will be made," Effati said.
A man said: "Hundreds of millions of dollars are not insignificant if there may be fatal flaws."
Another woman said the recommendations would not be available until mid-September, but the preliminary decision was slated for August.
"Our job as staff is to get as much information before the commission as possible," Craig Roepke, ISC bureau chief, said. "The commission makes its own schedule."
A woman asked if the commission has flexibility, to which Roepke replied: "Absolutely."