Tanzania: Drones help communities map flood risk in Dar es Salaam slums
With almost 70 percent of its inhabitants living in informal settlements, Dar es Salaam is highly vulnerable to flooding
By Kizito Makoye
The sight of a drone hovering above the streets of Tandale to map the crowded flood-prone neighbourhood in the north of Dar es Salaam spread excitement among inhabitants tired of dealing with regular inundations.
"I am happy to see something is being done to prevent flooding," said 35-year-old resident Happy Malimbo.
With the help of drones, city authorities are drawing up plans to protect and assist suburbs at risk of flooding like Tandale, offering a glimmer of hope to those who live there.
Since 2013, Dar es Salaam City Council has worked with the World Bank and other partners, including the Red Cross and the Open Geospatial Consortium, to plot roads, streams and flood plains using drones.
Dubbed Ramani Huria (Swahili for "Open Mapping"), the project aims to help communities in slums create accurate maps of their localities, which can be used to reduce flood risks and improve response to disasters, officials said.
Floods come every year to Tandale, one of Dar es Salaam's largest slums, but inadequate planning means the naturally occurring hazard often turns into a man-made disaster.
Local people say they have repeatedly suffered losses due to flooding, which has also left hundreds without shelter.
"I lost most of my belongings as the flood water stormed into the house in April this year," said Malimbo, who has three children.
With almost 70 percent of its inhabitants living in informal settlements, Dar es Salaam - Tanzania's largest city - is highly vulnerable to flooding, especially in densely populated slum areas like Tandale.
Heavy rains fall twice a year, often resulting in severe floods that force thousands of people from their homes and cause millions of dollars' worth of damage.
Juliana Letara, head of urban planning at Kinondoni Municipal Council, said the Ramani Huria initiative had trained university students and community members to identify and map areas mostly likely to be hit by floods, enabling local authorities to take action in real time.
Several wards in Tandale, in Kinondoni municipality, have been mapped to create flood risk models, and a community resilience plan has established evacuation routes.
"If you can trace where it floods, you can either install or upgrade infrastructure to improve the situation for the people," Letara told the Thomson Reuters Foundation.
The production of detailed datasets and collaboration with a separate Red Cross project to tackle flooding have led to the creation of local teams and plans for disaster preparedness and response in 10 of Dar es Salaam's most flood-prone communities.
"Ramani Huria maps are user-friendly - they can be used by people with any level of education," said Letara. "The community feels a sense of ownership over them because they were a part of the whole process."
"Now we have a map - and a map is something important to start with," said Tandale Ward Officer Osiligi Lossai. "We can identify different areas to restructure and improve. It is a roadmap for us to set up new plans (and) to organise ourselves while involving the community."
Officials in Tandale are also using the maps to work out where flooding could trigger disease outbreaks.
"With these maps, it is easy to identify houses with known cholera patients and allow an efficient response," said Lossai.
Drones provide high-resolution, real-time imagery which is needed to develop exposure maps and model flood risk.
Frederick Mbuya, a World Bank consultant working with Tanzania's Commission for Science and Technology, said drones are now a proven technology to conduct aerial surveys for land mapping.
"The use of drones is much cheaper than many other traditional methods," he told the Thomson Reuters Foundation
Kinondoni official Letara noted that drones can also help map areas that cannot be reached on foot due to flooding, highlighting the critical need for such a tool.
According to World Bank information officer Loy Nabeta, the data captured so far in the most flood-prone areas of Dar es Salaam, covering 1.3 million people, has been fed into publicly accessible online tools such as OpenStreetMap and InaSAFE, which can be used by communities.
Experts say most people who settle in flood-prone areas have little choice because they are poor, even if they know their lives and property are at risk.
As the rainy season does not last long, slum residents are willing to live with the threat of floods, soon forgetting the misery they cause, said Tandale resident Salum Kiponda.
But the Ramani Huria project could change the view that flooding is just something to be endured.
"We often don't know when the floods will come, and what to do, but this (new) information helps us know how to protect ourselves," said Malimbo.