Flash-flood event in Kampala observed with HyCRISTAL urban weather stations

Heavy rainfall that caused flash-flooding and at least two fatalities in Kampala in a period of heavy rainfall starting on 7 Sept 2020, was observed by HyCRISTAL’s urban network of weather stations.

Flooding has long been a problem in Kampala, and eight people died in floods in Kampala in May 2019. The floods affect homes, businesses, and other infrastructure and disrupt transport. Such floods have major knock-on effects on public health, by spreading effluent from sanitation systems and contaminating water supplies.

Climate change will increase rainfall intensities in East Africa, and HyCRISTAL is working with Kampala Capital City Authority (KCCA) and other groups such as the National Water and Sewerage Corporation (NWSC) to improve the resilience of Water, Sanitation and Hygiene (WASH) systems to flooding. One challenge is that weather stations are typically located out of urban areas, to avoid urban heat-island effects and wind obstruction by the dense cover of buildings, so localised high-intensity rainfall in urban areas is not directly observed. By working with the Ugandan National Meteorological Authority (UNMA), HyCRISTAL has addressed this issue by deploying urban rain gauges and weather sensors.

Flooding in Kampala, September 2020 (Source: Nicholas Bamulanzeki).

Such data allows scientists to build up an understanding of the events that cause flooding, and inform how infrastructure and WASH management must change to increase resilience. Combining these data with water levels measured in the local drainage network provides insight into the timing of flood peaks in response to intense rainfall events.

For further information on flooding in Uganda and East Africa see these resources: