Milly Mbuliro: Protecting the Nile Basin from the fury of flash floods 

Posted in : A View From The Field on 9 February 2026

“Today, the Nile Basin Flash Flood Early Warning System (NB-FFEWS) has forecasted flash floods to occur in the evening of tomorrow, Friday, March 28, 2025, in the eastern areas around Lake Victoria, in the Mara region” of Tanzania, Milly Mbuliro, a water resources officer at NELSAP-CU, broadcast to water colleagues on LinkedIn. Tanzania received far more detailed information about the expected time of the floods, their severity, specific locations at risk, and how many people might be affected.  

It’s deeply meaningful to Mbuliro, who led the two-year development of the CIWA-supported NB-FFEWS, that the system has been operating since June 2024.  

The impact of floods fills Mbuliro with sorrow. She sees the devastation during her field work travels throughout Nile Basin countries for her job, which includes serving as the coordinator for the NELSAP transboundary component of the Regional Climate Resilience Project and as the thematic lead for flood and drought risk mitigation under the Nile Cooperation for Climate Resilience (NCCR). Her work with NCCR includes traveling extensively to flood-prone areas to identify suitable interventions for improved flood-risk management and to prepare a flood management investment plan. 

“Flash floods occur very fast and without warning,” usually after heavy rains, says Mbuliro, 45, who is Ugandan but lives in Kigali, Rwanda with her two teenage children. 

Flash floods can last from 30 minutes to several hours and sometimes longer in flood plains. Unlike river floods, flash floods often take people by surprise—especially if there is no local rainfall—when water flows from the highlands to lower terrain faster than the ground can absorb. They also occur in cities when rain overflows inadequate drainage systems that are sometimes clogged with solid waste.  

Flash floods, which are arising more often and with more severity, can exacerbate food insecurity, cause disease outbreaks, and damage infrastructure.  

“The water came without warning” 

The Nile Basin experienced one of its worst flood years in 2024. In the spring rainy season, heavy rains caused severe flooding and flash floods across Burundi, Ethiopia, Kenya, Tanzania, and Uganda. By the end of the year, over 5 million people had been affected by floods, with hundreds of thousands of people displaced and hundreds more killed and injured.   

Over 293,000 Kenyans were forced to relocate from heavy rain and flash floods that spring. At least 315 people were killed. Hundreds of thousands of children missed school and the school meals they count on for sustenance. 

Mbuliro also saw the devastation in Kisumu, near Lake Victoria, that spring. “People fled their homes. They went to camps. Schools were abandoned. Health centers were abandoned.” Parts of the city around the lake were submerged for more than a month because of backwater effects (when water backs up or can’t flow downstream) from Lake Victoria. Since the water later in the lake is higher. 

“When you see that, you are moved to do something. . .to warn people to stay away or to protect the communities,” she says. 

The rains kept coming later that year.  In Ethiopia in the fall rainy season, Mbuliro saw deep gullies created by flash floods, splitting farms in half. “People told me, ‘We are unable to access our farmland. We lost our cattle. The water came without warning.’ ” 

The development of a life-saving system 

Flash flood early-warning systems can have a dramatic impact—saving lives, protecting health, and safeguarding livelihoods by mitigating adverse impacts of floods on agriculture and other economic activities. 

Before the NB-FFEWS, the Nile Basin Initiative (NBI) produced seasonal forecasts, which have limited use because of the sudden nature of flash floods. “Now we can warn communities with specific information on the location, magnitude, and time of the expected flash flood,” Mbuliro says.  

To develop the system, the NELSAP-CU first worked with the NBD and Nile Basin country experts to identify and map flash flood-prone areas. Then Mbuliro’s team, supported by consultants, developed the FFEWS, which relies on satellite-based rainfall forecasts from the Global Forecast System and its data on atmospheric and land-soil variables, including temperatures, winds, precipitation, soil moisture, and atmospheric ozone concentration using Remote Sensing technologies. 

The FFEWS then interprets how different parts of the Nile Basin are likely to respond to rainfall forecasts, based on such factors as whether the area is already saturated with water, large enough to absorb the rain, and has vegetation or is on a slope. Finally, it forecasts how severe the flash flood will be and the time it is expected to occur. The system updates information every 24 hours, releasing forecasts for the next 48 hours.  

Before deploying the NB-FFEWS through the NBI data portal, Mbuliro’s team developed a strategy to   operationalize the system to fit into countries’ existing early-warning information dissemination channels and trained country experts on how to access the system and interpret technical information. 

A critical link in the chain from the NB-FFEWS issuing a flash-flood forecast to communities receiving the warning is the capacity of national governments to distribute information using channels such as SMS messages, email, and national radio and TV. But Mbuliro says it doesn’t always happen. 

“We still have challenges,” she says. “It breaks my heart when the information does not reach the community in time. . . . I want to be part of the solution to reduce economic loss and loss of lives caused by floods. That’s what drives me.”