American farmers closely monitor their water needs to ensure they get a steady rhythm for irrigating crops. This is especially crucial in the Western U.S., where the majority of water used by people goes toward irrigation. Drought, climate change, and a growing population have made water increasingly limited. These dwindling resources must be used as efficiently as possible. The web-based platform, OpenET, measures evapotranspiration to drum up accurate water use estimates.
Our planet’s water cycle moves between evaporation, evapotranspiration, condensation, and precipitation to keep the water movingEvapotranspiration takes place when water leaves plants, soils, and other surfaces and returns to the atmosphere. Managing a water budget without an understanding of evapotranspiration is like trying to balance a checking account without understanding how much money you're spending.
Farmers use evapotranspiration to estimate the amount of water their fields and crops use. That water use needs to be replaced through irrigation or rainfall. Knowing how much water is transferred to the air allows farmers to better calculate crop water requirements. This helps them use water more efficiently and better plan irrigation.
"What OpenET offers is a way for people to better understand their water usage and, more importantly, their water loss through evapotranspiration," said Denise Moyle, an alfalfa farmer in Diamond Valley, Nevada, and an OpenET collaborator. "Giving farmers and other water managers better information is the greatest value of OpenET."
OpenET data is available on 17 western states, most notably the area covered by the Colorado River basin. It uses Landsat satellite data, supported by open-source software and open data sources. The platform creates a consistent, accessible source of “truth” that keeps water managers and other decision makers on the same page. Before OpenET, organizations would often get different measurements, which would lead to confusion and debates over accuracy.
"OpenET brings together several well-established methods for calculating evapotranspiration from satellite data onto a single platform so that everyone who makes decisions about water can work from the same playbook, using the same consistent, trusted data," said Robyn Grimm, OpenET’s project manager and the director of Climate Resilient Water Systems at the Environmental Defense Fund.
As farms, vineyards, and other growers in the U.S. West try to maintain production levels despite environmental challenges, OpenET allows them to make data-driven decisions and improve their water management practices. Some collaborators using the tool have reported water savings of up to 20%.