So, what did you do on your last summer vacation? Whatever it was, chances are Shreesh Karjagi has you beat. The Kenyan-raised UCLA student flew 8,000 miles to Indonesia with blueprints for his own big idea — a new, cheap and easy way to clean agricultural water in rural communities.

The rising senior had learned all about phytoremediation, or deploying plants to filter contaminated water, in Professor Shaily Mahendra’s environmental microbiology classes at the UCLA Samueli School of Engineering. A self-defined “third-culture kid,” raised with multiple worldviews, he saw a need for a simple method to improve traditional irrigation systems without upsetting social or economic balances.

And then a stroke of good fortune: a UCLA post seeking volunteers to work in a Balinese farming community.

A farming village in Sibang Kaja, Bali

Karjagi left Westwood to spend the summer working alongside 250 farmers in the Astungkaraway cooperative in Sibang Kaja, miles from Bali’s tourist beaches. The challenges were both social and technical. Karjagi had to persuade the locals to help him build his device, a web of rafts framed by discarded plastic piping holding grasses that would filter the water running through rice fields and homes. It took weeks of adjustments to make the rafts strong and stable enough.

“I knew from my own background how vital safe water is, but some well-intentioned solutions have been expensive, prone to failure and seen as coming from outside, from the West,” he says. “I wanted to get around that by working with the villagers using materials that were already there.”

He recalls the locals’ excitement when the first five-by-two platform was locked into the ancient waterways. People watched with rapt attention as the raft’s dangling grasses, called vetiver, cleansed the water as it flowed through, almost magically removing fecal matter, chemicals and debris. It was remarkably effective: Tests showed the once-murky water was now safe for irrigation.

“It will stop children falling ill with stomach issues,” says Karjagi, who says he hopes to inspire his peers to work with communities of color most affected by environmental change.

His mentor, Mahendra, is proud of Karjagi and others who go into the field — in his case, very far afield — to share their UCLA-gleaned knowledge. “Good engineering, whether it’s massive projects or very local,” she says, “makes a difference in so many lives.”

Read more from UCLA Magazine’s Spring 2023 issue.

UCLA Magazine Spring 2023 Cover