Satellites can show us how much water is used for irrigation

Water conservation and management have always been central to agriculture, with irrigation being the primary consumer of this resource. 

A report from the European Space Agency notes that we use more water for irrigation than for any other single purpose, yet lack global monitoring of these practices.

As the global demand for water surges, predominantly due to increasing populations and the climate crisis, scientists are exploring innovative solutions to this challenge. 

One promising solution involves using satellite data to measure how much water is utilized for irrigation.

Eyes in the sky

More than 70% of the water extracted from Earth’s surface or underground resources is used for irrigation. Surprisingly, there’s limited monitoring of this massive water diversion, especially when it’s a direct interaction with Earth’s natural water cycle. 

Recent advancements in satellite technology might be the answer to this oversight, according to a recent study published in the journal Earth System Science Data. 

The report reveals that ESA’s Science for Society Irrigation+ project has shown potential in using space-based information to measure irrigation levels.

Valuable satellite data 

The research, led by the National Research Council and the University of Perugia, expands on previous studies that used soil moisture data from satellite missions, such as ESA’s SMOS, as well as evapotranspiration information. 

The experts used an “inversion technique” that transforms these broad satellite data into the first regional high-resolution irrigation water datasets.

Irrigation estimates 

“We developed these datasets for three major river basins that are irrigated differently and have different climatic conditions,” explained study co-author Jacopo Dari.

“Using data from the Copernicus Sentinel-1 radar mission and a soil-moisture inversion technique, we achieved irrigation estimates with 1 km resolution over the semi-arid Ebro river basin in northeast Spain and the wetter Po valley in northern Italy.

“Over the Murray-Darling basin pilot site in southeast Australia, which is also semi-arid, we achieve irrigation estimates of 6 km resolution using soil moisture data from NASA’s Cyclone Global Navigation Satellite System.”

Invaluable datasets 

The datasets derived from this research, spanning from 2016 to 2020 for the European regions and from 2017 to 2020 for the Murray–Darling basin, provide detailed insights into current irrigation practices. 

They also lay the groundwork for improved water resource management in the face of increasing demands and potential scarcity.

Study implications 

As the world faces the increasing challenges of balancing food production and environmental sustainability, tools such as these satellite-based monitoring systems become indispensable. 

The ultimate goal is for global water usage – especially for agriculture – is not just an estimate but a measurable and manageable figure.

“We are delighted that our Science for Society Irrigation+ project has yielded 23 scientific publications in peer-reviewed journals and the first regional-scale gridded irrigation datasets retrieved from satellite observations at a spatial resolution suitable for water resource management in agriculture,” said ESA expert Espen Volden.

“They could lay the foundation for developing a system for monitoring water irrigation in high-resolution from space, which is much-needed given the pressure that our freshwater supplies are under now and the fact that they will be under even more pressure in the future.”

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