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You can’t grow food without water – but in many parts of the world, there isn’t much water to spare.

Now, two alumni of the University of Toronto’s Faculty of Applied Science & Engineering have developed a solution they think could help.

Austin Mclean and Rashmi Satharakulasinghe are the co-founders of Corridor Water Technologies, a social enterprise that aims to commercialize a passive water irrigation controller for use in areas without electricity.

“Irrigation is water intensive, but it can be made a lot more efficient if you only turn on the water when the plants require it,” says Satharakulasinghe. “There are a number of smart sensing systems available to help farmers make that call, but right now they all require electricity, which isn’t always available to farmers outside of the developed world.”

The team’s solution grew out of research conducted over the past several years in the lab of Amy Bilton, an associate professor in the department of mechanical and industrial engineering. Bilton and her students . Bilton continues to serve as a senior adviser to Corridor Water Technologies.

Known as a passive irrigation controller system (PICS), the team’s device includes a probe that is capable of sensing how wet or dry the soil is via physical and chemical characteristics. Using a property known as “soil suction pressure,” the device mechanically opens or closes a valve to regulate the flow of water – all without the use of electricity.

“We have been through numerous iterations of the design, experimenting with different materials and mechanical principles,” says Mclean. “We are still looking to improve some of the smaller mechanics of the design and integrate unique options where possible.”

Austin Mclean and Rashmi Satharakulasinghe demonstrate the electricity-free irrigation controller they developed to help farmers in developing countries make more efficient use of water in agriculture (photo by Corridor Water Technologies)

By turning irrigation on and off automatically to maintain a desired soil saturation level, the PICS can reduce water use by up to 20 per cent compared to current practices of flood irrigation. Farmers can “set it and forget it,” freeing up time for other tasks while secure in the knowledge that their plants won’t get too dry or too wet, and will grow at their optimum rate.

“We designed our device to be simple in terms of features, operation and maintenance,” says Satharakulasinghe. “It can easily be tuned to the different crops common in the community, or even adapted for new crops that would help farmers diversify their range.”

In June of 2020, Corridor Water Technologies , a competition organized by the American Society of Mechanical Engineers. The win netted them a US$10,000 seed grant, which they have been using to further improve their design, as well as one-on-one coaching sessions with industry professionals.

“We have been fortunate that during the pandemic we had access to a U of T greenhouse to do testing in,” says Mclean. “This summer we are planning to expand our field testing, hopefully including warmer areas closer to the conditions of our intended farming community outside of Canada.”

Satharakulasinghe says that in addition to agricultural benefits, the PICS could have several social benefits in the communities where it could one day be deployed.

“Often in these communities, it is the women of the household who run the farming activities while the men travel to the city for labour work,” she says. “By bringing additional income to the family, PICS could also promote gender equality.”

“These types of projects provide students with opportunities to work across cultures and disciplines at the same time as addressing a hard and constrained engineering challenge,” says Bilton. “Austin and Rashmi are doing a fantastic job, and it’s very rewarding to see a group of former students take some tech which was developed in our lab and turn it into a venture like Corridor Water.

“The reason we do the work we do is to have an impact.”