Sudden flood in Barmer(2006) causing devastation in a large area and heavy casualties in the northwestern part of India: A meteorological study

Category Environmetal Geology
Group GSI.IR
Location International Geological Congress,oslo 2008
Author Sisodia, Hari Singh۱; Paliwal, Bhawani Shanker۲
Holding Date 06 October 2008

The sudden flood over the Barmer and Jaisalmer districts of Rajasthan in the northwestern part of India in August 2006 caused a large devastation rendering over two thousand families of Kawas and Malwa villages which are still submerged under more than a metre thick flood water. The Hydro-meteorological and Geological studies of the Barmer-Jaisalmer 2006 flood which affected around 8 lack people and equally large number of livestock revealed interesting results. The area due to heavy rainfall (600 mm against normal annual of 200 mm) flooded the depressions and plains particularly underlain by clays-bentonite and fullers earth of the Tertiary age and gypsum strata of the Quaternary period. The most affected villages include Kawas and Malwa. To understand the real cause of the sudden flood in the area a meteorological study was under taken. The study reveals a close correspondence between the resultant wind direction and the orientation of longitudinal and parabolic dunes. The resultant wind directions at Jodhpur and Barmer in May to August are WSW to SSW. At Jodhpur 18%.of the total days of May to July have the wind speed range of 20.92 to 61.25 kmph. At Barmer 6% of the total number of days of May to July have wind speed range of 20.92 and 61kmph. At Deesa wind speed doesn’t exceed 1.6 to 19 kmph. Wind speed range during these 3 months cause sand shifting since moderate and strong winds blow from west and south west directions. The other predominant directions of the wind are northwest and southeast during winter but these are weak and cannot shift sand. These do not disturb the evolutionary continuity of dunes. The axial directions of the dunes of the old and new systems are the same which indicate practically no change in the wind regime. It was observed that due to insufficient downward percolation of water the conditions worsened and devastation took place. The clay has the Permeability of the order of 0.0004 meters per day. Therefore the desiccation of flood water will depend upon the rate of evaporation and of the terrain as well as the solar radiation. The annual rate of evaporation on the basis of average monthly wind rose diagrams of Barmer upholds with the Fitzerald’s Empirical Equation amounted + 2.0 meters per year and have been verified with the Open Pan Evaporimeter data of 2 meteorological stations at Barmer and Jaisalmer. Observations support a normal monsoon for the country and denied to connect with any climatic changes. The multidisciplinary study for this Geological- Meteorological Action Center, highlighting good impacts for ecological advantages and forecasting for a new land use pattern to be executed to minimize such devastation in future. Whereas the observable facts demand very detailed study in context of the thermal energies released at every strong seismic spell in the sea bottoms and tend to the oceanic currents temperature variation and resultantly the weather systems triggering in torrential rains and heavy floods.