“Our team focused on the area of Bwaise, an urban slum in Kampala, Uganda, which is known to be increasingly prone to flooding. It is a low-lying, densely urbanised area that inhabits a low-income population – some of them earn less than one US dollar a month. We found that waste management is a major problem within this settlement. Due to the lack of opportunities for locals to get rid of their waste, the garbage mostly ends up in open areas and drainages, clogging the sewage system. Moreover, the area is located in a former wetland and water coming from upgradient areas all accumulates in this low-lying area. Add to that the inadequate drainage system, poorly constructed houses, and the problem of climate change, resulting in more frequent and intense rainfall events, and you will understand why this area is highly affected by floods.
We wanted to improve the resilience of the slum against the floods, first of all by implementing floating mechanisms in houses, with water storage units underneath the houses. This would prevent the houses from being completely inundated in case of a flood, but instead, the floor would float on the surface of rising floodwater.
Such floating floors would only help the inhabitants to deal with the floods once they occur, but of course, this intervention would not prevent or decrease floods in the future. That is why we tried to model flood patterns. Through this, we found that the primary drainage overflows easily because the water is discharged very slowly, whereas the velocity in the secondary drainage is relatively high, which is why the water is discharged quickly into the primary channel. Based on this, we proposed to increase the velocity of discharging water by hardening and steepening the primary drainage, and on the other hand to slow down and store the water in the secondary channel, with the concept of sustainable urban drainages. Moreover, we proposed to improve waste management by having central waste disposal centres, in order to prevent waste clogging in the sewage system.”
