USDA atlas shows diverse efforts to fight Southwest water scarcity
Researchers from the U.S. Department of Agriculture have created a searchable atlas that compiles regional research and efforts to deal with water scarcity and drought.
The map, called the Water Adaptation Techniques Atlas, was developed by the agency’s Southwest and California Climate Hubs and so far contains 183 case studies from Arizona, California, New Mexico, Nevada and Utah.
“Ultimately one of the main groups we want this to be useful for are agricultural producers, especially irrigation water users,” said Noah Silber-Coats, project lead for the atlas.
The map offers a range of case studies, many of them related to agricultural and ranching practices, crop choice, and irrigation methods.
Silber-Coats hopes it can be a resource for agricultural professionals and advisers, like cooperative extension workers.
But the online resource is also intended for conservation practitioners, urban planners, water providers and others.
Selected case studies include improvements in agricultural practices, market-based solutions, state-led groundwater recharge projects, water leases and settlements — anything that responds to the current water scenario.
“As the Atlas grows this can become a resource for learning about what has been done elsewhere in the region and to support diffusion of effective practices,” Silber-Coats added.
Searchable archive dates back years
The online tool is part of the efforts of USDA regional Climate Hubs to produce useful science-based information for resource managers.
Climate Hubs, created in 2014, operate under the Agricultural Research Service and the Forest Service, and work with other department agencies to support applied research, provide guidance and help education and outreach.
The mapping tool documents efforts, old and new, to cope with water scarcity.
Broadly, cases are organized by ways to use less water, ways to get more water, and ways to change where water goes. Search filters, like the type of solution, the main use of the water, and the scale at which the solution is implemented, help users narrow down their work.
Many of the case studies include experiments or pilot programs, including efforts from decades prior that proved unsuccessful or even harmful.
A study from the 1970s found higher yields and lower water use in sorghum crops sprayed with a chemical that reduces the amount of water vapor coming out of the plant leaves as it grows. Decades later, research showed the product at play, called phenylmercuric acetate, was extremely toxic and a serious health hazard.
The area of research is still promising. Around the 1980s scientists tested other products, similar to liquid wax, on invasive species like the tamarisk, or salt cedar, which has taken over long stretches of Arizona rivers. The USDA often controls the invasive species by spraying large quantities of herbicide, sometimes by helicopter.
Products like that liquid wax could be an alternative to reduce the amount of water the trees take from desert rives, while also avoiding the side-effects of putting herbicide in the landscape, Silber Coats said.
The online map does not provide any silver-bullet solution. All cases have pitfalls and might solve one problem while creating another or might not work in a certain location.
“It’s important to know what’s been tried even if it’s found unsuccessful,” he added. “Just as there are antiquated ideas, there are other things that are very valuable.”
Native crops and new technologies are included
The tool also includes information on trials and traditional farming practices with heirloom varieties, drought-tolerant crops that, for countless generations, Indigenous people have selected, improved and cared for, such as tepary beans, maize, buffalo gourds and heirloom chiles.
Native grasses with high tolerance to salt, like saltgrass (Distichilis spicata), have also been noted in other studies as a potential alternative forage.
Simple, well-known agricultural practices like alternating crops, intercropping, establishing cover crops instead of leaving land bare, and increasing the amount of organic matter in the soil, are also represented in the map.
In eastern New Mexico, field experiments looking for alternative forage crops found the highest nutritional value and lowest water use came from winter crops growing a mix of wheat and peas, or triticale and peas.
Other case studies include N-Drip’s low-pressure drip irrigation system, experiments that about the use of brackish water on salt-tolerant crops, and drought-tolerant crops that could gain a place within emerging markets, like guayule, lesquerella, camelina and jojoba.
What comes next
The online tool serves as a collection of studies and practices, many tested many years ago, and the team expects to evaluate the outcomes of those practices in the future.
“The Intergovernmental Panel on Climate Change (IPCC) has a framework that we will borrow from, rating water adaptation practices in five dimensions on a continuum from strongly positive
adaptation to maladaptive,” SilberCoats said.
“In the current format it takes some interpretation and critical thinking from users.”
The team is open to receive comments on existing case studies in the atlas and suggestions on new ones. People can write to noahsc@nmsu.edu, or leave a comment on the form linked to the website.
Clara Migoya covers environmental issues for The Arizona Republic and azcentral. Send tips or questions to clara.migoya@arizonarepublic.com.
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