Management of Flash Floods – Capacity Building and Awareness Raising in the Hindu Kush Himalayas
The Himalayas are one of the youngest mountain ranges on earth and represent a high energy environment very much prone to natural disasters. High relief, steep slopes, complex geological structures with active tectonic processes and continued seismic activities, and a climate characterised by great seasonality in rainfall, all combine to make natural disasters, especially water-induced hazards, common phenomena.
Flash floods are among the more devastating types of hazard as they occur rapidly with little lead time for warning, and transport tremendous amounts of water and debris at high velocity. There are several different types of flash flood including intense rainfall floods, glacial lake outburst floods (GLOFs), landslide dam outburst floods, and floods caused by rapid melting of snow and ice or failure of dams and other hydraulic structures. They affect thousands of people in the Himalayan region every year – their lives, homes, and livelihoods – as well as expensive infrastructure, and the threat is likely to increase in the face of climate and environmental change. However, there is limited capacity in the region to manage flash flood risks.
In recent years, ICIMOD has embarked on a number of initiatives aimed at reducing the vulnerability to flash floods in the Hindu Kush-Himalayan region, including developing a systematic inventory of glaciers and glacial lakes in the region, and identifying glacial lakes in danger of bursting. To improve understanding of the nature of the problem and identify potential flash flood management measures, ICIMOD organised an ‘International Workshop on Flash Floods and Sustainable Development in the Himalayas’ (see related resources) in Lhasa, PR China in 2005 together with the China Meteorological Administration (CMA) and World Meteorological Organization (WMO), and with support from the Government of Norway and USAID Office of US Foreign Disaster Assistance (OFDA). The workshop was the starting point of a process aimed at reducing flash-flood vulnerability in the region within the context of sustainable development and poverty reduction. As a direct outcome, ICIMOD undertook a project on ‘Capacity Building for Flash Floods Management and Sustainable Development in the Himalayas’. The 18-month first phase from June 2006, funded by USAID/OFDA, focussed on a baseline assessment of flash flood risk management in the region and strengthening the capacity of key stakeholders in the region to manage flash flood risk. Capacity building modules were prepared on flash flood risk management and key stakeholders were trained.
Building on this, a further two-year phase on ‘Management of Flash Floods – Capacity Building and Awareness Raising in the Hindu Kush-Himalayas’ has been initiated with support from USAID/OFDA.
Conclusion – Impacts of climate change on flash flooding
Intense rainfall ﬂoods and landslide dam outburst ﬂoods are directly related to the hydrometeorological conditions and likely to be affected by climate change. Climate models project an increase in monsoon precipitation in the region. Similarly the frequency and magnitude of extreme rainfall events are also anticipated. GLOFs are related to glacial retreat which in turn is mainly due to climatic warming. It is therefore very likely that ﬂash ﬂoods due to intense rainfall, landslide dam outbursts, and glacial lake outbursts will increase in the future.
January 2008-December 2009, China, Nepal, Pakistan.