Contribution of flood early warning response measures in reducing flood effects in Kilosa District, Tanzania

Abstract

Floods, caused by natural and human-induced factors, are devastating to human livelihoods and the environment. Measures such as flood early warning are used to mitigate their effects, but little is known about how response measures reduce the effects of floods in flooded areas including Kilosa District, Tanzania. To add information in this gap, 375 household heads were surveyed, 20 key informants were interviewed and 17 participants took part in focus group discussions. The results show that the flood response measures have reduced human deaths, injuries and property damage or loss. The reduction in flood effects was significantly associated with family discussions on preparedness (p < 0.0001) and evacuation from risk areas (p < 0.0001). The study concludes that residents actively respond to warnings, thereby reducing damage to themselves and easily movable assets. To improve the effectiveness of early warnings, it is recommended that housing be located away from flood-prone rivers, local disaster committees and upstream communities be trained to recognize flood signs, and community flood emergency response training be provided.

Practical implication

Flooding is a disaster that has occurred repeatedly in the current century and is predicted to increase in the near future due to escalating climate change (Intergovernmental Panel on Climate Change [IPCC], 2022), rapidly growing human populations in flood-prone areas (Getahun et al., 2021), and unplanned settlements (Nyam et al., 2024, Williams et al., 2019). To counteract it, mitigation measures through early warnings are vital, as they make the vulnerable community prepared for what is coming. For early warnings to be effective in mitigating the effects of floods, they must be easy to understand, reliable and actionable (United Nations Disaster Risk Reduction-USDR, 2017). Similarly, understanding the contribution of response measures in mitigating the effects of flooding is paramount. It is therefore essential to assess the contribution of measures taken by vulnerable communities to respond to flooding, to help decision-makers design better interventions and to enable communities to make informed choices to manage the effects of flooding. To achieve this goal, the study was specifically designed to assess key outcomes threatened by floods. These key outcomes include (i) human lives at risk of death and injury, and (ii) property damage or total loss. These outcomes are derived from the conceptualisation of this study as shown in Fig. 1. This study finds that the main initiators of flood early warning are the local people and experts/officials from the government and private stakeholders at the pre-flood stage. The flood early warnings provided are generated and transmitted by local and modern early warning systems (EWS). The responders to these warnings are the people in flood-prone areas at the individual and community (collective) levels, who then have to take voluntary or mandatory measures before and during flood events (onset time). Such measures include running, climbing on roofs or trees, informing others and moving to uplands (safe areas). When properly implemented, these measures reduce the number of deaths, injuries, property damage and losses.

From the preceding arguments, the practical implications of the study are as follows:

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  Flood early warnings are essential tools for mitigating the effects of floods, especially for households in flood-prone areas with previous flood experience. However, improving the dissemination of warnings is crucial. This can be achieved by building community capacity to use a variety of traditional channels and tools including drums, whistles and cow horns. Expanding the use of these locally available methods will improve response capacity and ensure that households receive timely warnings from multiple sources, allowing for early action and better preparedness.
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  Response measures taken by household members in response to early flood warnings are crucial to reduce the number of deaths, injuries and property damage or loss. The reduction of flood effects is significantly associated with proactive measures including communicating with family members about safety plans and early evacuation from high-risk areas. These actions highlight the importance of timely decision-making and coordinated family preparedness in minimising the effects of floods.
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  Most respondents emphasized that the greatest contribution of early warning measures is in reducing human deaths and injuries, followed by reducing effects on livestock and easily movable household assets. Continued efforts should therefore focus on maintaining and improving these outcomes, as they are integral to the livelihoods of rural communities in the study area. Given the projected increase in flooding due to on-going climate change (IPCC, 2022), improving early warning remains essential.