How can satellites measure crop water use from space? Can they help farmers irrigate more precisely, improve yields, and make water distribution fairer across canal systems?

In this episode of the Water Data Podcast, Veena Srinivasan speaks with Professor Wim Bastiaanssen, a pioneer in satellite-based evapotranspiration mapping and the original developer of SEBAL — the Surface Energy Balance Algorithm.

Professor Bastiaanssen explains how satellite imagery can estimate actual evapotranspiration, soil moisture, crop water stress, and irrigation performance by combining land-surface temperature, vegetation data, and the surface energy balance. The conversation traces the journey from early field validation of SEBAL to its application across farms, irrigation systems, and river basins around the world.

Wim and Veena discuss how farmers can use simple satellite-based advisories to identify dry patches in their fields, prevent crop stress, and use water more productively. They also explore how the same data can help irrigation agencies understand whether canal water is reaching head-end and tail-end farmers equitably.

The episode further examines water accounting, data-model integration, the commercialisation of scientific tools, and the growth of platforms such as IrriWatch and HydroSat. It is a wide-ranging conversation on evapotranspiration, precision irrigation, water productivity, and how satellite data can support water security at scale.

The Water Data Podcast is a talk show on the science, systems, and stories of water, hosted by Veena Srinivasan.

For all references and further readings related to the episode, visit https://welllabs.org/wim-bastiaanssen/

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Recording by Anukriti Shaw, Nabina Chakraborty and Vraj Acharya and Video editing by Srisabari Varaguna Pandian. Graphics and artwork by Aparna Nambiar, Kanishka Goyal and Oishika Goswami. Audio mixing and mastering by Vijay Doiphode. Podcast production and management by Nabina Chakraborty and Pavan Srinath.