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Keywords: Remote sensing; Floods; Hydrodynamic model; Swat.
1. Introduction
Natural hazards are intense conditions that exist inside the natural environment (atmosphere, biosphere, hydrosphere and lithosphere) and have diverse capabilities of causing damages to both life and property. These extreme events have significant impact on the socio-economic system of the human settlement (Alexander, 1993). Like other natural hazards, hydro-meteorological hazards such as floods and storms, dominated major portion in the mass of natural disasters. It was found in the year 2010, that natural disaster including floods and storms displaced about 42 million people around the world (UNEP/OCHA, 2010). According to the disaster statistical report for the year 2013 by the Centre for Research on the Epidemiology of Disasters (CRED), showed that hydrological events (floods and mass movement (wet)) still claim the largest (48.2%) share in comparison to other natural disasters (Fig. 1).
Pakistan is a disaster-prone country due to its geo-physical and climatic conditions. The country is severely affected and still prone to different natural hazards i.e. hydro-meteorological, geo-physical and biological (NDMA, 2013). Among the natural hazards, flood's is the most frequent and complex natural disaster in the country followed by earthquakes, cyclones and drought (ADB, 2008; UNEP/OCHA, 2010). In the last 65 years the Pakistan economy has set back with a cumulative financial shock of more than US$ 39.055 billion due to different flood disasters (GoP, 2012). The floods of 2010, was ever worst in the history of the country, which caused widespread damages across the Pakistan, killing about 1985 people, 2,946 got injured, over 1.6 million homes were destroyed and 20 million people were seriously affected (NDMA, 2010; GoP, 2012).
The number of people affected was high in comparison to other disasters such as the 2004 Indian Ocean Tsunami, the 2005 Kashmir Earthquake, Cyclone Nargis 2008 and the 2010 Haiti Earthquake (Table 1).
Swat district located in the northern part of the country is vulnerable to frequent floods (Nasir and Khan, 2011). In the area, floods are mainly induced by rainfall in the form of erratic and cloud burst and summer snow-melt especially in the late monsoon season i.e. July to September. This heavy downpour of the rain also aggravate secondary hazards such as landslides, mudslides, soil erosion and sediment deposition downstream (Rahman and...