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Chad

Chad | Floods - Simplified Early Action Protocol (sEAP No: sEAP2023CD01)

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RISK ANALYSIS AND SELECTION OF EARLY ACTIONS

Priority risks and their impacts.

Chad remains exposed to the effects of climate change according to analyses of the Climate Change Vulnerability Index (CCVI). On the other hand, the analysis carried out by Verisk Maplecroft (a monitoring and advisory organization on risks in the world), also shows that Chad is one of the most vulnerable countries in the world to climate change. The resurgence of extreme weather events, such as floods, droughts, heat waves and strong winds, is one of the highlights of climate change with enormous humanitarian consequences for the population.Table 1: INFORM Index

In Chad, the rainy season runs from June to September (Fig. 1a). The south of the country is wetter, due to the greater proximity to the equator. Monthly totals reveal that the months of July and August are the wettest (Fig. 1b) with monthly totals of up to 300 mm in places. This rainfall, combined with Chad's general topography, of the plain type, exposes it to two types of flooding: river and rainfall. The history of floods in Chad goes back several decades. In 1988, floods were recorded in a dozen regions, affecting about 47,000 people. Those of 2022 represent for most people the largest floods known in Chad. The toll was indeed very heavy: 18 of the 23 provinces affected, 977,501 people affected, 465,030 hectares of crops flooded, 162,917 households affected, 78,949 houses destroyed and 19,399 head of cattle swept away. In N'Djamena, they affected about 192,337 people, including 32,050 affected households (OCHA, 2022).

The recurrence of floods in recent years, especially those caused by heavy rains (which are sudden) make this hazard one of the main concerns for the population and public authorities. Rainwater flooding occurs when a more or less significant amount of rain falls on a locality, following one or more consecutive rainfall events, without the hydraulic infrastructure being able to contain the water. This, combined with low soil permeability, means that water ends up invading homes as well as infrastructure and public works (schools, bridges, etc.) leading to significant human and material damage. The general topography of Chad, of the plain type, exposes it to the recurrence of this hazard. However, the weakness of the data collection system means that no distinction is made on the type of floods when reporting the impacts. Data on flood impacts are therefore common to both storm and river floods.

In terms of period of occurrence, rainfall floods are most often recorded between July and August, when maximum intensities are recorded. This is illustrated in Figure 1b using the occurrence of percentile 99 (i.e. the amount of water that is greater than 99% of the amounts recorded during rainfall) of the daily totals.