Unique public-private partnership brings together NASA, USGS, Google, Environmental Defense Fund, and more to make scientifically rigorous evapotranspiration data widely available
Press release from OpenET
OpenET, a nonprofit initiative dedicated to providing easily accessible satellite-based data for improved water management, has expanded its online platform to cover the contiguous United States.
OpenET released daily and monthly data on evapotranspiration (ET) for the eastern half of the U.S. at a spatial scale of one-quarter of an acre per pixel. The data are freely available through OpenET’s easy-to-use Data Explorer, Application Programming Interface (API), and mobile-friendly Farm and Ranch Management Support (FARMS) tool.
The release represents an expansion of OpenET to 25 more states. The platform originally launched in 2021 with data in 17 western states and expanded to 23 states in 2023. Today, OpenET has more than 13,000 registered users who routinely retrieve data for a wide variety of applications, ranging from irrigation scheduling for individual fields to water accounting across major U.S. river basins. OpenET also launched a redesigned website (https://etdata.org/) and logo to coincide with the U.S. expansion.
“The expansion of OpenET is a major milestone for making critical water data even more widely accessible for landowners and water managers across the U.S.,” said Sara Larsen, CEO of OpenET. “While OpenET launched with a focus on western arid regions confronting major drought, we know these data will be valuable to landowners and water managers across the country who want to better understand patterns in ET. For instance, resource managers can use OpenET to track water trends over time across large regions to evaluate the effectiveness of different forest and rangeland management plans.”
“It’s all about finding new ways to make satellite data easier to access and use for as many people as possible,” said Forrest Melton, the OpenET project scientist at NASA’s Ames Research Center in Silicon Valley. “The goal is to empower users with actionable, science-based data to support decisions about water management.”
“Before OpenET, getting water use data was challenging and cost prohibitive for the majority of farming and ranching operations,” said Maurice Hall, senior advisor, climate resilient water systems, at Environmental Defense Fund. “Thanks to a unique public-private-philanthropic partnership, OpenET makes critical water data widely accessible for all landowners across the United States, serving as an invaluable tool to help accelerate testing and adoption of more sustainable and innovative water management practices.”
“As a partner from day one, Google is thrilled to see OpenET expanding their ET data to all 48 contiguous U.S. states,” said Karin Tuxen-Bettman, Google Earth Engine Program Manager. “OpenET is a powerful example of how Google Earth Engine and technology can support the sustainable management of our planet’s critical natural resources, in this case water. Water is fundamental to the health of our planet and people, so we are celebrating this significant step by OpenET and look forward to ensuring this data gets into the hands of people who need it most to sustainably manage our water resources.”
Filling a critical gap in water management
OpenET fills a major information gap in water management. While water is essential to our food supply, communities, and economies, getting access to accurate, timely ET data has been fragmented and often expensive, keeping it out of the hands of many farmers and decision-makers. OpenET allows users to easily view and download this important water data for current and recent years (since 2016) for free.
The latest expansion of OpenET to the East Coast makes this important water dataset available at high resolution (30 meters x 30 meters or 0.22 acres per pixel) but does not yet include any field boundary data. Field-level water data are expected to be available for the eastern half of the country in early 2026.
In addition to providing water data in the U.S., OpenET is being expanded to provide data for Brazil to better understand drying trends and the impact of land use changes on the Amazon River Basin.
“OpenET provides real-time insights into crop water use that farmers have never had before,” said Dwane Roth, a semiretired fourth-generation Kansas farmer and advocate of producer-led innovation. “When combined with soil-moisture probes, OpenET helps producers grow more with less water — a game-changer for the next generation of agriculture.”
“I am excited to have OpenET covering most of the United States because it has huge potential to improve the management of plantations in the southeast and forest management in many areas of the U.S.,” said Yun Yang, an OpenET board member and assistant professor at Cornell University’s School of Integrative Plant Science.
Yang has used ET data for research on a North Carolina Loblolly pine plantation and natural forests in Missouri and New Jersey. “Having data from OpenET at my fingertips instead of needing to run calculations on my own, as I have done in the past, will significantly accelerate my research on the relationship between evapotranspiration and forest and plantation thinning as well as drought-induced tree mortality,” Yang added.
Applications of OpenET
Since its launch in 2021, OpenET has been used in a wide variety of ways, from the farm to the multistate scale. Current applications include:
- Irrigation management: From an individual landowner to large companies including Gallo and Sun Pacific Farming, OpenET helps growers of all sizes estimate crop water demand to optimize irrigation, maintain or improve yields, and reduce costs. OpenET data can be integrated into platforms that include soil moisture, nutrient data, and other inputs to guide irrigation scheduling. By providing cost-effective and often more accurate ET information, OpenET enhances the performance and affordability of these decision-support tools. For example, it’s been estimated that incorporating field-scale OpenET data into irrigation scheduling just for California almond orchards could generate $127.5 million in savings and total economic value for water users over a five-year period. California grape growers also report up to 25% water savings by integrating OpenET tools into their irrigation management practices.
- Groundwater accounting and management: Water agencies in California and Nebraska are using OpenET in an open-source groundwater accounting platform, developed by EDF and partners, to help farmers track and manage their water budgets, while agencies in Oregon and Kansas are in the process of developing pilot projects with the accounting platform.
- Water use reporting: The California Central Delta Water Agency and South Delta Water Agency use OpenET as an alternative means to support water use reporting to the state, which has led to an increase in landowner reporting and significant cost savings for farmers in the Delta.
- Consistent data for river basin management: The U.S. Bureau of Reclamation, four states of the Upper Colorado River Basin (CO, UT, NM, and WY), and the Upper Colorado River Commission officially adopted one of the OpenET models to serve as the basis for irrigated agricultural consumptive use measurement across the upper basin.
- Conservation programs: OpenET supports the development, implementation, and monitoring of agricultural water conservation programs to reduce consumptive use in water-stressed regions.
What is ET?
The “ET” in OpenET stands for evapotranspiration — the process in which water evaporates from the land surface and transpires, or is released, from plants. ET is a key measure of water consumed by crops and other vegetation that can be used by farmers and water managers to better track water use as well as water saved, for instance, when farmers change crops or invest in new technologies.
The “Open” in OpenET refers to the commitment of the nonprofit, OpenET science team, and broader consortium of public- and private-sector partners to providing open access to these data with no cost to view, download, or use it within standard usage limits. OpenET combines satellite information with local weather data to accurately calculate ET using six independent models and an ensemble ET value, which have been developed over several decades by leading scientists. OpenET runs on Google Earth Engine, which provides a shared geospatial computing platform that allows the OpenET science team and software engineers to efficiently collaborate to produce open, high accuracy, reproducible and scientifically-based data for the U.S.
ET can be computed by satellites because the ET process absorbs energy and cools the land surface, and vegetation reflects and absorbs different amounts of visible and near-infrared light depending upon the density and health of the vegetation. These effects are visible to thermal and optical sensors on satellites like Landsat, as well as the ECOSTRESS instrument onboard the International Space Station.
OpenET data have been extensively compared to ground-based measurements collected in agricultural fields and natural landscapes, and tested by a wide variety of organizations through several use cases to ensure the highest accuracy.
Additional Resources:
Media contact: Ronna Kelly, media@openetdata.org
Media Kit: Click here.
Stories from the field: https://etdata.org/openet-for-growers/
YouTube: https://www.youtube.com/@openetdata4047
LinkedIn: https://www.linkedin.com/company/openetdata/
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About OpenET
A public-private collaboration led by NASA, USGS, California State University Monterey Bay, Environmental Defense Fund, Desert Research Institute, Google Earth Engine and HabitatSeven, OpenET uses publicly available data produced by NASA, USGS Landsat, and other satellite and ground-based systems to calculate evapotranspiration rates at the field level. OpenET is supported through federal, state, and philanthropic funding to ensure the dataset remains accurate, reliable, and publicly accessible.
