Researchers Use ​Satellite ​Images to ​Produce Annual ​Maps of ​Irrigation

How much water flows into agricultural irrigation? New study provides 18-year water use record.

Irrigation for agriculture is the largest use of fresh water around the globe, but precise records and maps of when and where water is applied by farmers are difficult to locate. Now a team of researchers has discovered how to track water used in agriculture.

Source: Wikimedia Commons

In a paper published in the journal  Geophysical Research Letters , the researchers detail their use of satellite images to produce annual maps of irrigation. The findings, the scientists said, will help farmers, water resource managers and others understand agricultural irrigation choices and make better water management decisions.

"We want to know how human activities are having an impact on the environment," said hydrogeologist David Hyndman of Michigan State University (MSU), principal investigator of the project. "Irrigation nearly doubles crop yields and increases farmer incomes, but unsustainable water use for irrigation is resulting in depletion of groundwater aquifers around the world. The question is: 'How can we best use water?'"

The paper highlights the need to know when and where irrigation is occurring to effectively manage water resources.

The project focuses on an economically important agricultural region of the central U.S.--the Republican River Basin--that overlies portions of Colorado, Nebraska and Kansas, and provides surface water and groundwater to the High Plains Aquifer. The team found that irrigation in this area roughly doubled between 2002 and 2016.

Water use in this region can be complicated because it is regulated to preserve stream flow into Kansas in accordance with the Republican River Compact of 1942.

"Previously, we knew what farms were equipped to irrigate, but not which fields were actually irrigated in any particular year," said Jillian Deines, also of MSU and the paper's lead author. "Our irrigation maps provide this information over 18 years and can be used to understand the factors that contribute to irrigation decisions."

The researchers used Google Earth Engine, a cloud-computing platform that makes large-scale satellite and environmental data analyses available to the public, to quantify changes in irrigation from year to year--an important finding for farmers, crop consultants and policymakers working to improve the efficiency of irrigation.

Google Earth Engine has been an asset for computing the large number of satellite images needed, the scientists said. "It allows researchers to use consistent methods to examine large regions through time," Deines said.

Read full article: NSF

Media

Taxonomy

• Agriculture
• Irrigation
• Water Footprint
• GIS
• Consumption
• Irrigated Landscapes
• Satellite
• Data & Analysis