Open Science & Transparency
Committed to Transparency in Data & Methods
At OpenET, we believe that trust begins with transparency. That’s why we openly share information about the data sources, modeling methods, and assumptions behind our evapotranspiration estimates. By making these details accessible, we empower users to understand the strengths and limitations of the data and apply it with confidence in their own water management decisions.
Why is ET Important?
ET is the second-largest component of the water cycle (after precipitation), and it plays a critical role in determining water usage. Understanding ET is key to both local agricultural irrigation decision-making and large-scale water sustainability planning.
Many Factors Affect ET
ET varies not just by water availability and crop, but also by soil type, irrigation system, ground cover, plant age, and more. Keep this in mind when comparing ET across fields or regions.
ET vs. Water Applied
While ET helps computes a plant's water needs, total irrigation may exceed ET due to salinity management, frost protection, or system inefficiencies. Conversely, some perennial crops can tap deep moisture and thrive even when irrigation is below actual ET values.
Combining Data Sources
For best results, pair OpenET data with other on-farm or regional data—like diversion amounts, crop yield information, and irrigation scheduling data.
Important Considerations
Use of data from the Data Explorer is subject to OpenET’s terms of service.
- 1 Free API usage is limited by monthly quotas.
- 2 The Data Explorer provides a rolling 5–6 year archive.
- 3 The API enables access to longer-term data, with 30+ years available for some areas.
Learn More About OpenET Science
Data Methods
Information about the models, input datasets, and compute resources used by OpenET.
Accuracy & Known Issues
Field-scale accuracy assessments and known issues that impact OpenET data.
Literature & Research
Browse published papers about OpenET data and associated research.
Filling the Biggest Data Gap
in Water Management
As we expand globally, our mission remains the same: deliver open, reliable, and actionable water data—developed with users, for users.