Rio Grande Basin-wide project addressing water challenges for agricultural sustainabilityBy Kathy Wythe
A team of 20 researchers representing Texas Water Resources Institute (TWRI), Texas A&M AgriLife Research, Texas A&M AgriLife Extension Service, New Mexico Water Resources Research Institute and New Mexico State University has completed its first year of a $5 million four-year grant from the U.S. Department of Agriculture’s (USDA) National Institute of Food and Agriculture (NIFA) to address these water challenges and ensure agricultural sustainability in the basin.
The project, “Diversifying the Water Portfolio for Agriculture in the Rio Grande Basin,” is led by Dr. John Tracy, TWRI director. The project is funded as part of NIFA’s Agriculture and Food Research Initiative authorized by the 2014 Farm Bill.
Researchers are investigating alternative water sources that can be used for irrigation and conserve groundwater and the Rio Grande’s freshwater. They are also evaluating the use of drought- and salt-tolerant crops, new crops and new management practices — all to diversify the water resources and sustain agriculture in the basin.
“Unless new approaches are implemented to better use the limited water resources or develop nontraditional water supplies within the Rio Grande Basin,” Tracy said, “there will be limited opportunities for economic development and the sustainability of the agricultural economies throughout the basin could be threatened.”
Tracy said in the long term, the project team hopes to develop an economic and water management assessment framework that will help evaluate the impact that innovative water technology and agricultural management practices have on water sustainability and agricultural productivity within the basin.
“The assessment framework will provide water resource managers with tools to help increase the efficacy of water use and agricultural profitability throughout the basin and develop a better understanding of the role that nontraditional water resources can play in enhancing sustainable water management within the basin,” he said.
One of the objectives of the project is to evaluate the water availability in the Rio Grande Basin at current and projected future scenarios in light of changing climate, water management and demographics to understand the impacts that these factors have on the region’s water supplies. Led by Dr. Raghavan Srinivasan, professor in Texas A&M University’s Department of Ecosystem Science and Management, the team is using models such as the Soil and Water Assessment Tool (SWAT) hydrologic model.
In year one, an initial hydrologic model was built and run using the web-based interactive water quantity and quality modeling system — Hydrologic and Water Quality System or HAWQS — that employs SWAT as its core modeling engine.
“Given the large basin size and the considerable human intervention that has altered the hydrologic regime, significant computational resources are required,” Srinivasan said. “Thus, the basin-wide model at this stage intends on gaining insight into a viable modeling strategy.”
Dr. Girisha Ganjegunte, associate professor at the Texas A&M AgriLife Research Center at El Paso, leads the efforts to demonstrate the appropriate use of alternative water sources, such as treated wastewater, graywater and brackish groundwater, to extend the availability of existing freshwater supplies.
“We are conducting greenhouse studies to evaluate the salinity tolerance of pomegranate, cotton, guar, canola, switchgrass and energy sorghum as well as field experiments in El Paso and Weslaco, Texas, and Artesia, New Mexico, with those same crops irrigated with alternative water sources to evaluate their performance when grown on soils affected by salinity,” Ganjegunte said.
Because the management of water is so essential to the long-term sustainability of the basin, team members are developing research and demonstration tools focused on improving irrigation management within the basin, according to Dr. Sam Fernald, director of the New Mexico Water Resources Research Institute.
In the first year of the project, Fernald said, team members began acquiring and processing data for evapotranspiration (ET) calculations in the Mesilla Valley in New Mexico to eventually compare to ground level ET measurements. Researchers also began defining the scope, expected use and functionality of an ET decision support tool.
“We identified nontraditional sources of ET data that could potentially aid in understanding crop water demands,” Fernald said.
As part of the project’s objective of identifying the most economically efficient use of fresh and marginal water supplies to increase the value of water use, researchers examined the possibility of a dry year option. Dr. Bruce McCarl, professor in Texas A&M’s Department of Agricultural Economics and lead for this objective, explained that a dry year option is a water market where cities in the Lower Rio Grande Valley of Texas could acquire water on a temporary basis by leasing it from agricultural producers.
“The water supply in the basin is unstable because of increased recent droughts and reduced deliveries from Mexico along with increased Mexican dam construction and water consumption,” McCarl said. “Such a program would improve water performance in agriculture by giving farmers sale-based incentives to conserve and would provide water for the growing nonagricultural use under dry conditions,” he said.
McCarl said the development of an integrated hydrologic-economic modeling tool was also initiated in year one. This tool will be used to understand the changes in water management practices, crop selection and the use of nontraditional waters will have on agricultural economic output.
According to Dr. Askarali Karimov, AgriLife Extension specialist in Texas A&M’s Department of Biological and Agricultural Engineering and lead for the outreach objective, the project held four outreach events in the basin with more than 500 participants.
“Engaging stakeholders at these events proved to be valuable because of the ability to secure key individuals who represent the diverse water interests from across the basin for the advisory board,” Karimov said. “We also presented at five other events on water conservation methods, solar pumping applications, water allocations in the Rio Grande, common farming limitations and water sampling techniques for on-farm water quality management.
Additionally, the New Mexico State University Irrigation Interpretation Excel workbook was introduced to small farm water users in an effort to help producers estimate leaching fractions based on soil and water sample analysis and crop water demand.
Tracy said with the continued research and education, the project should improve the long-term viability and resiliency of agriculture within the basin.
“The outcomes of this project will increase our understanding of how the use of all available water resources can be optimized to provide the greatest societal value within the basin by sustaining agricultural production while enhancing regional water use efficacy, economies, ecosystem services and employment opportunities,” he said.
For more information, contact Tracy at John.Tracy@ag.tamu.edu.