Senegal: Staying home at all costs

​When a neighbourhood is at risk of flooding, the most logical solution is to build new houses in more secure areas and to relocate the residents. But in Dakar, the capital of Senegal, things are not so simple.

The Sahel region experienced a long period without precipitation in the 1970s, ‘80s, and ‘90s. “During a drought, rural populations migrate to the cities,” explains Oumar Cissé, executive secretary of the Institut africain de gestion urbaine. Thus in Dakar, families moved to areas considered to be “humid” but that had long been dried up. “The problem is that the rain returned about ten years ago,” says Cissé. “So, hello to all that water damage!”

In the capital and its over-populated suburbs, floods often affect tens of thousands of homes. “If the rains settle in permanently, we risk seeing half the suburb struggling with this kind of problem,” explains the researcher.

In 2012, the Senegalese government established a $1.5 billion assistance program, which included the construction of drainage infrastructures and the development of new neighbourhoods. However, the researchers were surprised to note that the families from flooded neighbourhoods often chose to stay where they were instead of moving. Why? Cissé explains that the residents of vulnerable neighbourhoods generally earn their living in the informal economy, for example as vendors at the local market. Relocation could mean losing their livelihood. He adds that a third of the residents of Yeumbeul North, a Dakar suburb, settled in this community after the region was impacted by serious floods. Rather than leave, the people adapted to the climate’s variability. Some demolished their houses, raised their land, and rebuilt. “Half of those who rebuilt their house after the floods were spared,” comments Cissé on the subject of the Yeumbeul North community.

But this did not solve everything. During flooding, the sandy roads became impassable and septic tanks overflowed. Instead of moving the people, the team from the Institut africain de gestion urbaine focused on the construction of drainage channels, retention ponds, pumping stations, and PVC septic tanks, which are more water-resistant.

Cissé thinks that Senegal’s cities have a vested interest in quickly finding the solution to their infrastructure problems because rainfalls could intensify in the coming years. “We have normal rainfalls of 200 mm per year. But what will happen when we get 900 mm of rain?”

The original French version of this article was published in the December 2015 issue of Québec Science.