Mozambique generally has two seasons: wet and dry. When it rains, it can flood; when rainfall is scarce, crops dry up. Civil engineer Aline Okello saw how this pattern affected local farmers, who see their crops flooded year after year only to lose out again come the next big drought. So she decided to help.

After studying water science and management in the Netherlands – another low-lying country prone to floods – Okello began to understand Mozambique’s problems in a new light.

“I was seeing all these windmills, all these wheels pumping water, and I thought, ‘My God, I didn’t know about this [technology] and I’m a civil engineer,’” she says.

Okello considered the technologies on hand in Mozambique, including those available to the poorest communities, and realised they generally all have access to the same modern-day tool. “They won’t have water or electricity, but they will have a mobile phone – often a smartphone – and apps like WhatsApp,” she says.

“That got me thinking: we don’t have enough reservoirs, and we have only limited water management and infrastructure, so there is a huge need for growth and technology. People don’t have any idea how much water they can actually save from their rooftops. There is a huge information gap.”

So she developed a rainwater harvesting app – one that would source reliable, live precipitation data from Nasa, as well as giving users a step-by-step guide to how harvesting works.

The app relies on inputs for roof type (clay, thatch, iron sheets) and location to determine how much water can be harvested every day and month, given the locale’s average precipitation. Once this information is provided, the app suggests the best size of harvesting tank and informs users where to buy the necessary equipment, including tanks, pipes and pumps. Although most manufacturers are in South Africa and ship to Mozambique, Okello expects the local industry to expand as demand grows.

Should rainwater harvesting succeed, it could help to tackle the huge problems facing residents in the region. Mozambique, much like the rest of southern Africa, has suffered from a prolonged drought that began in March 2015 and worsened with this year’s El Niño. Crops have been devastated, livestock killed off, bore holes dug and evaporated, and residents forced to scavenge for wild fruit and vegetables.



Aline Okello’s rainwater harvesting app has earned her a place on the shortlist for the Africa prize for engineering innovation. Photograph: James Oatway/The Royal Academy of Engineering

The extended drought has left about 3.2 million children in southern Africa without access to clean drinking water, according to the UN Office for the Coordination of Humanitarian Affairs. The expected arrival of La Niña, which normally brings floods to southern Africa, has prompted residents to dig large holes that they hope will serve as reservoirs. But such floods can carry serious waterborne diseases, further exacerbated by contaminated water supplies and lack of access to sanitation.

Okello’s app has been a great success in rural South Africa, where she has been trialling it with local communities also affected by the recent drought.

Ultimately, says Okello, her goal is to inform residents how to use the technology that is available to them, in a manner that helps them adapt to an ever-changing climate: “My vision really is to bring information to people’s fingertips.”

• Aline Okello’s app was shortlisted for the Royal Academy of Engineering’s Africa prize for engineering innovation