Sierra Leone Rapid Damage and Loss Assessment of August 14th, 2017 - Landslides and Floods in the Western Area

from World Bank, GFDRR
Published on 14 Aug 2017 View Original

Executive Summary

A massive landslide in the Western Area Rural of Sierra Leone on August 14, 2017, slipped into the Babadorie River Valley and exacerbated existing flooding in the Western Area Rural and Urban (Freetown), affecting about 6,000 people of which 1,141 have been declared dead or missing.

Following three days of intense rainfall, a mountain valley side slope in the Regent area below Sugar Loaf, the highest peak in the north of the Western Area Peninsula, collapsed and caused a major landslide. According to eye witness accounts, the landslide took place in two stages—with the lower part of the slope slipping into the valley, and 10 minutes later, the upper part of the slope. The two-stage slip, and particularly the second, comprising a mix of clayey soil and boulders of all sizes (up to 40 cubic meters) traveling from high up the slope, would have had tremendous energy and momentum. Residents reported a large ‘tidal wave’ of material advancing down the river channel immediately after the landslide as the debris pushed the flood water in front of it.

The damage and loss caused by the landslide and subsequent debris flow along the Babadorie River Valley differed significantly from that caused by the flooding in other valleys across Freetown City. The main landslide caused major destruction in infrastructure, including buildings, bridges, schools, and health facilities in the Regent, Malama/Kamayama, Juba/Kaningo, and Lumley areas. Flooding in areas outside the landslide zone affected 55 percent of the households in the Culvert and Dwazark neighborhoods of Freetown on the same day. The value of real estate damages and losses was higher than that of the other infrastructure sectors, which is typical of a disaster caused by a natural hazard event in an urban area (Figure 1).

Damage impact also varied by geography, with lower income settlements being at the recipient end of the floods. Based on the satellite imagery and wardlevel census data, differences in the quality of housing can be clearly distinguished along the water course and area of impact. The more upstream housing close to the landslide in Regent were better built and larger in size, whereas closer to the ocean, informal settlements dominated the urban landscape (Figure 2).

The Government of Sierra Leone requested the World Bank’s support to conduct a comprehensive rapid Damage and Loss Assessment (DaLA), in partnership with the United Nations (UN). The DaLA was carried out from August 24 to September 8, 2017, with the objective of estimating damages and losses and of making preliminary estimations for mobilizing funds and launching immediate recovery.

The assessment covers ten sectors, four cross-cutting areas, and preliminary recommendations for immediate, medium-, and long-term needs. UN agencies and other development partners will support the formulation of a programmatic plan covering key institutional, policy, financing, and implementation actions.

This DaLA is a living document and, as such, is subject to revisions as additional data become available. The report has sought to outline what is desirable and what is possible. The next step is to commence upon a recovery framework, which the UN will lead with the government, to guide and coordinate recovery and reconstruction efforts.