Towards resilience to pluvial flood events

Many growing cities in Low and Middle Income Countries, experience flash floods on an annual basis, exacerbated by inadequate draining systems and increased permeable surfaces from rapid and unplanned urbanisation, resulting in in little opportunity for individuals and infrastructure to recover. Pluvial flooding is a hazard for a wide range of often, already fragile, interdependent infrastructure sectors: water and waste water, transport, energy generation and distribution, solid waste and ICT, as well as housing and livelihoods. Flood-related losses and damage to people's property is escalating, as is the cost of maintaining roads and drainage channels. The hazard also increases the incidents of water borne diseases such as cholera, typhoid, dysentery, and malaria. Flood events typically occur in low-lying areas often occupied by informal settlements, however, the wider, knock-on effects on transportation, economy, and infrastructure also influence middle and upper income groups; with whole cities becoming exposed.
Early warning systems for weather events are limited to predicting rapid, high magnitude events such as hurricanes or slow onset events such as droughts, with little attention paid to rapid, low magnitude events such as flash flooding from intense rainfall that typically last between 2 and 6 hours and can therefore only have limited impact on reducing the risk from pluvial flooding.

The aim of this catalyst project is to understand the hydro-meteorological factors that lead to pluvial/flash flooding and the impact this hazard has on local communities and their supporting infrastructure. Furthermore this project will test the transferability of three impact models to that will better prepare communities and emergency services to respond in a pluvial flood event and inform decision makers on how to improve infrastructure resilience.

Demonstrated in Kampala, Uganda, this catalyst will address the five objectives:

1. Explore past impacts of, and current vulnerability to extreme rainfall, capitalising upon existing data and tools, and local knowledge.
2. Characterise extreme rainfall associated with pluvial flooding in the city of Kampala.
3. Enhance understanding of the location and magnitude of impacts of pluvial flooding to people and infrastructure to assess pluvial risk as a function of hazard and impacts.
4. Assess effective responses and preparation to enhance resilience to pluvial extremes.
5. Co-create appropriate communication mechanisms to enhance the uptake of risk and resilience information in practice by communities, NGOs, and local government agencies.

The research will benefit a wide range of stakeholders including: individuals and communities by providing appropriate information for them to be better prepared during pluvial flood events and to change behaviours and take measures to adapt to the risk; emergency services and responders who could make use of the disruption risk mapping to support response and recovery during pluvial flood events; local authority and infrastructure providers will have improved evidence of where to target adaptation to limit direct and indirect impacts on housing, infrastructure, the economy and livelihoods.

This catalyst research will demonstrate how the approaches used could be combined with real time weather predictions to support the development of a real-time Decision Support System during pluvial flood events.

This research project will primarily benefit the following stakeholders:

Individuals and communities: equipping individuals and communities with information on the nature and impact of the hazard of pluvial flooding will enable them to be better prepared during extreme events in terms of following appropriate evacuation routes, contributing to saving lives and access to disaster relief. Furthermore, understanding the potential impacts of pluvial flood risk empowers individuals and communities to take measures, and change behaviours to adapt to the risks, limiting the potential impacts on their homes and livelihoods, and to put pressure on the appropriate authorities to take action and change policies and practices.

Emergency services and responders: Understanding risk and vulnerability, can complement humanitarian response during flood events ultimately improving resilience of people and infrastructure if communicated at the appropriate spatial scale. For example, disruption risk mapping would be beneficial to emergency services who support response and recovery in terms of being aware of changes to transport accessibility.

Local authority (Kampala Capital City Authority) and local infrastructure providers: will benefit from the co-designed outputs from the impact models to help them identify vulnerability 'hotspots' to pluvial flood risk and where best to target adaptation of infrastructure to minimise direct damage impacts and indirect disruption impacts. Pluvial flooding can adversely impact housing, infrastructure, the economy and livelihoods; evidence provided can help inform risk reduction strategies that limits the effect of pluvial flooding on livelihoods and economic development.

Other academics: Newcastle University will share two unique, transferable models with the research team at Makerere; these could be incorporated into Master's courses at Makerere University. There will also be benefit to UK researchers to rethink models and methods for application to African context, in particular handling informal processes, and to improve UK research impact.