eNews February 2019

NMT Student Using NM WRRI Funding to Study Sediment Flow in Arroyos

by Thom Guengerich, NM Tech Office of Communications and Marketing


New Mexico Tech doctoral student Kyle Stark is putting his NM WRRI grant to good use. He is conducting a multi-year study of sediment transport in an ephemeral arroyo near Socorro.

Stark, along with his advisors and other funding agencies, constructed a monitoring station on the Arroyo de los Piños, which is a seasonal tributary to the Rio Grande. That arroyo only runs a few times each year, but the flow can provide significant sediment transport into the river.

The Rio Grande is a crucial part of life in the southwest United States. Constant maintenance along these rivers is required to ensure that the adjacent communities have consistent access to water, to prevent avulsions and the development of sediment plugs, to manage reservoir infilling, and to maintain aquatic habitat for life in the Rio Grande.

One source of uncertainty in managing these rivers is the sediment incoming from arroyos and other dry river channels. Flowing water in these channels is rare, but sediment production can be high when they do flow.

“The Rio Grande is connected to the surrounding landscape via these ephemeral channels,” Stark said. “We are trying to improve our models to help manage the rivers in these arid environments.”

Stark’s NM WRRI funding helped him fund a student worker during the 2018 monsoon season and the installation of additional instrumentation. NM WRRI funding allowed Stark to install an instrument to measure water velocity at in large flows. Prior to that, his only way to measure water speed was to wade out into the stream. “This new method is not nearly as dangerous,” he said.

The Arroyo de los Piños system was designed and constructed to be a premier sediment monitoring station. Funded by the U.S. Bureau of Reclamation and the U.S. Army Corps of Engineers, Stark’s array of sensors incorporates peer-reviewed methods of monitoring water and sediment with novel approaches that are new to the arid Southwest. The goal is to better understand the mechanisms that transport water and sediment down these dry riverbeds into their mainstem counterparts. Armed with these unique datasets, river managers at the local, state, and federal level will be better prepared for a changing Rio Grande. Researchers can study other dry channels in desert regions all over the world with technologies developed on the Piños. As these mainstem rivers become more managed, communities can better prepare for changes that happen along them.

The Bureau of Reclamation engineered and built the station that has three key features:

  • Stabilized banks using rip-rap in Gabion baskets;
  • Automated instruments that measure sediment and upload it to the cloud; and
  • An array of instruments that were deployed to be passive and not interfere with flow.

The heart of the monitoring station is a Reid-type slot sampler system with three pit samplers, which are chambers below the river bed that capture rocks, gravel, and sand as a flood rolls, slides, or bounces them down the channel.

Stark, along with his advisors Dr. Dan Cadol of NMT and Dr. Jonathan Laronne of Ben-Gurion University of the Negev in Israel, have added an array of other sensors.

Stark is collecting data from these five “surrogate sensors”:

  • Impact pipe microphones, which record the sound of sediment hitting the pipe
  • Plate microphones that also record impacts
  • A vertical pipe microphone that records different modes of bed load transport
  • Two pairs of hydrophones that record the sound-scape of the bed load and turbulence in the water
  • Seismometers that measures the vibrations caused by bed load and turbulence

Stark said that for every flood, the array collects 22,000 data points. The real key is finding which instrument works best in these sandy, flash-flood-dominated channels. He said that parsing out the signals is the challenge. “My Ph.D. primarily will be based on data from the pipe sensors and plate sensors.”

“What’s novel about this site is that we are using six different ‘surrogate’ methods to measure sediment transport,” Stark said. “This combination of methods has not been tested anywhere in the U.S. in tandem. We are trying to find out which instruments work best for these ephemeral tributaries. We hope to find answers so that in the future, rather than deploying a huge set of instruments, we can calibrate a smaller array of sensors to do it more efficiently.”

eNews February 2019

Meet the Researcher: Laura J. Crossey, Department of Earth & Planetary Sciences, University of New Mexico

by Catherine Ortega Klett, NM WRRI Program Manager


Laura J. Crossey joined the faculty at The University of New Mexico in 1986 and became the first woman tenured, the first woman named full professor, and the first female department Chair in the Department of Earth & Planetary Sciences. Her research group explores applications of low-temperature geochemistry to problems in hydrochemistry/water quality, diagenesis, geomicrobiology, and geothermal processes. Her research approach combines field examination of modern environments (water, gas, geomicrobial materials and sediments) with laboratory analysis as well as core and outcrop study to evaluate paleohydrology, spring sustainability, and reservoir/aquifer characteristics.

Professor Crossey received a BA in geology from Colorado College (Colorado Springs, CO) and an MS, also in geology, from Washington University in St. Louis. She earned her PhD from the University of Wyoming in deep-basin sedimentary diagenesis.

Dr. Crossey has received many honors, including several for her efforts in promoting women in science and technology. In 2015, she received the Ninth Annual IMPACT! Award from the New Mexico Network for Women in Science in Engineering. She is also a Fellow of the Geological Society of America (since 2010), and is the 2019 Birdsall Dreiss Distinguished Lecturer for the Hydrogeology Division of GSA. She was awarded Lifetime Membership to the New Mexico Geological Society on the basis of her service. She and her husband Karl Karlstrom were awarded an Outstanding Achievement Award by the American Institute of Professional Geologists in 2015 for designing and building the Trail of Time, a geoscience exhibition at the Grand Canyon installed in 2010.

Professor Crossey has supervised 63 graduate students (MS and PhD) and 63 undergraduates. She has had four NM WRRI Student Water Research recipients since the program began 2003. Three of the four students she advised, Dennis Newell, Matthew Kirk, and Amy Williams are all now professors in water-related research-intensive departments. Her most recent advisee, Jon Golla, is headed to a prestigious PhD program at the University of Illinois, Champagne-Urbana. “The WRRI opportunities are a marvelous preparation for graduate students: from writing the grant to budgeting the resources and completing a report. This is excellent training for a geoscientist, whether heading for academia, industry or other opportunities in the federal or state arena.” says Dr. Crossey.

eNews February 2019

NMSU Student Investigating the Chemical Treatment of Water Produced as a Byproduct of Oil and Gas Production in New Mexico

by Catherine Ortega Klett, NM WRRI Program Manager


Lei Hu, a PhD graduate student in the Department of Civil Engineering at New Mexico State University, is working on a grant project funded by the New Mexico Water Resources Research Institute (NM WRRI) titled “Recovery of Ammonium and Magnesium from Produced Water by Struvite Precipitation.” His faculty adviser is Dr. Yanyan Zhang, also of the Department of Civil Engineering at NMSU.

Oil and natural gas industries generate huge amounts of produced water containing a complex mixture of organic contaminants and very high concentrations of inorganic salts. Pollution problems related to the ammonium (ionized ammonia) discharge of produced water commonly include eutrophication and dissolved oxygen depletion in water bodies, as well as toxicity to aquatic life. Therefore, high concentrations of ammonium in the produced water is a major hurdle for the treatment and reuse of the produced water. A particularly promising chemical treatment for the removal and simultaneous recovery of ammonium and magnesium from the produced water is to precipitate it out in the form of a relatively insoluble compound of magnesium, phosphorous and oxygen (as phosphate), ammonium, and water, known as struvite.  This white crystalline mineral can also be put to good use as a slow release chemical fertilizer, which therefore helps to make this approach to water treatment economically viable.

The main objective of this project is therefore to simultaneously recover ammonium and magnesium from produced water by struvite precipitation. The optimal conditions for struvite formation are being explored by considering the different effects of salinity, organic composition, solution pH, concentration ratios of the various ionic components that react to form struvite, and the presence of other competitive metal ions, such as those of calcium and potassium, on the production of struvite. For example, by the addition of excess phosphate to the produced water, calcium will also precipitate out as calcium phosphate, along with the struvite. The removal of such calcium from produced water can help to minimize the calcium-based scale formation that fouls membranes that are used to carry out the desalination of produced water.

The phosphate that is needed for these precipitation reactions can potentially be obtained partially from the wastewater itself, and from the anaerobic sludge of wastewater treatment plants. It is therefore anticipated that these precipitation processes will be found to provide an economical pathway for the removal of ammonia, magnesium, phosphate, and calcium from produced water, while at the same time providing a beneficial mineral for use as a chemical fertilizer. Considering the low cost and relatively simple technology, the struvite and associated calcium precipitation processes have considerable economic potential for large-scale applications.

Lei Hu expects to graduate with a doctoral degree in civil engineering in July 2021. He came to NMSU from China where he received bachelor and master degrees from China University of Mining & Technology in Beijing. Lei presented his project at the New Mexico Produced Water Conference in Santa Fe last November. He met with an engineer from the Mosiac Company who was very interested in the research and who also believes that struvite precipitation is a good method to recover ammonium and magnesium from produced water.

Lei also presented his project at the NM WRRI’s 63rd Annual New Mexico Water Conference in October 2018. He says, “I was so happy to meet other students conducting water-related research. My career goal is to become an expert in the wastewater treatment field and solve some water pollution problems.” Lei added that the NM WRRI student grant was very helpful in providing him with the financial support to work on developing new research about produced water.