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Atlas of Lebanon

Part 5 - Major Environmental Issues

Risks (II): Floods and Human Activities

Chadi Abdallah

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1Floods frequently occur in Lebanon during the rainy season, usually between December and March after particularly heavy storms or at the beginning of snowmelt. Rivers overflow causing major damages, which are estimated to amount to 15 million US$ per year. These events are more and more studied and seem mostly related to anthropogenic factors, including uncontrolled urban sprawl.

An increasingly frequent phenomenon?

2There has never been a systematic recording over time of floods in Lebanon, which makes their impact difficult to assess. A survey of the events mentioned in the press was conducted by a team of the NCSR. These figures should be treated with caution, as they may partially reflect the growing attention paid to this issue by the media and public opinion. Nonetheless, one can observe a distinct increase in the number of reported events, with a total of 23 since 2000. Several factors could explain this trend. The increase in the number of torrential rains over the past decades, at least partly linked to climatic trends on a smaller scale, certainly contribute to the multiplication of the number of episodes. However, anthropogenic factors appear to be the most determining ones.

3The expansion of built-up and urban areas goes on without any restrictive regulatory measure being implemented: the construction of roads and bridges over waterways, of buildings on their banks, and their use as drop-off points for rock materials and waste greatly increase the vulnerability of these zones.

Figure V-9: Floods reported in the press in Lebanon

Figure V-9: Floods reported in the press in Lebanon

Significant consequences on agricultural land and infrastructure

4Nearly two thirds of the reported damages have affected agricultural activities and infrastructure, especially roads. During several intense episodes, entire crops were lost, including in the Akkar and the Bekaa Valley in 2003, and the road network became unusable on several occasions, even leading to schools closing for three days in January 2013. More than 15% of the reported damages affect houses and the number of casualties, 41 since 1975, shows that these events are also deadly, even if this figure remains low compared to what it rises to elsewhere. The consequences of these floods are all the more significant as the Lebanese government is not able to provide sufficient compensation packages, while the affected population is sometimes composed of low-income families, such as in the Akkar.

Figure V-10: Casualities and damages caused by floods in Lebanon according to the press

Figure V-10: Casualities and damages caused by floods in Lebanon according to the press

5These findings have led the Lebanese NCSR to launch a program aimed at assessing flood hazard, in collaboration with the UNDP. All the risk areas located in the watersheds of perennial rivers, particularly vast in the Bekaa Valley and the Akkar, have been mapped in detail with a focus on three issues: land use, damages to the built structure, and to agricultural land. For 10-year floods happening between December and February across the Lebanese territory, it has been estimated that losses caused by damages to agricultural land could amount to 3 million US$ and the ones caused by structural damage to 60 million US$. 748 km of roads would be impacted. For 50-year floods, 82,000 individuals would be affected. The examples of Ghadir and Ras Baalbek clearly show the effects of the growth of built-up areas and the presence of agricultural land and industrial facilities in the heart of flood-prone areas.

Figure V-11: Impacts of floods in urban and agricultural contexts in Lebanon

Figure V-11: Impacts of floods in urban and agricultural contexts in Lebanon

Table des illustrations

Titre Figure V-10: Casualities and damages caused by floods in Lebanon according to the press
URL http://books.openedition.org/ifpo/docannexe/image/13272/img-1.png
Fichier image/png, 13k
Titre Figure V-11: Impacts of floods in urban and agricultural contexts in Lebanon
URL http://books.openedition.org/ifpo/docannexe/image/13272/img-2.png
Fichier image/png, 534k

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