Overview

Sri Lankan cities are becoming increasingly vulnerable to the effects of natural disasters. The recent floods have had devastating socio-economic impacts on large segments of the Sri Lanka’s population and economy. The after-effects of flooding are especially dire in densely populated urban settlements, in particular coastal settlements, which account for about 43 percent of Sri Lanka’s GDP.

Challenge

Colombo Metropolitan Area (CMA), the capital city of Sri Lanka, is one of the Sri Lanka’s urban areas most exposed to floods.  The occurrence and damage of urban floods in the Colombo Metropolitan Area has steadily increased over time due to a combination of climatic and non-climatic factors. Fast urban growth, coupled with unplanned patterns of human settlements and land use, have lead to encroachment of canal reservations, further exacerbating the risk for flooding. Studies have shown that the rainfall intensities in Colombo basin have also increased over the last 30 years. 

Colombo metropolitan area covers only about 6 percent of the country’s total land area and is home to 28 percent of its population, it accounts for almost 50 percent of national GDP and 80 percent of industrial value added. A major flood in the basin is estimated to affect more than 2.5 million people directly and indirectly. In addition, in Colombo City alone, there are around 68,000 housing units in under-served pockets, most of which are in flood-prone areas, and subject to the environmental and health risks of floods every year. The CMA has experienced two major flood events in May 2010 and November 2010 affecting more than 300,000 people directly. This highlighted the need of developing a comprehensive flood mitigation strategy for the CMA. 

Approach

The World Bank has approved a project of USD 213 million for Metro Colombo Urban Development and the majority of the investments will be for the urgent interventions needed to mitigate floods. The bank also will be supporting the government to develop a comprehensive flood mitigation strategy for CMA. A detailed risk assessment will be carried out using CAPRA tools to develop flood risk maps which can be used in the development of the Flood Mitigation Strategy and the other urban development initiatives in the area.

There had not been any comprehensive initiative in Sri Lanka to assess risk on the urban environments and the proposed project will provide a unique opportunity to enhance the capacity of Sri Lankan experts to carry out urban risk assessments. Prior to the risk assessment exercise, a three days’ training program has been organized to train Sri Lankan professional on Probabilistic Risk Assessment using CAPRA.

Results

The Risk Assessment exercise using CAPRA will generate a high resolution flood risk map for Colombo metropolitan area which will be useful for the urban planners in designing future development activities in the area. The results of the risk assessment will also be used by the emergency management agencies such as the Disaster Management Centre to prepare for response. The project will be a great opportunity for Sri Lankan risk assessment professionals to master in the CAPRA application so that the local experts can apply CAPRA in the other flood prone basins.