Spatial and Temporal Analysis of Drought over Godavari and Beas Catchment

Abstract

On the basis of daily precipitation data of 34 grid points in Beas Basin and 63 grid points in Godavari Basin from 1951-2013, droughts were investigated with respect to spatial and temporal characteristics. Godavari River Basin is located within the geographical co-ordinates 16°16′ N - 23°43′ N and 73°26′ E - 83°07′ E having total catchment area of 3,12,812 Sq.km. Beas River Basin is located within the geographical co-ordinates 31°28'N- 32°26'N and 75°56'E - 77°48'E. The catchment area of Beas river basin is around 12,560 km2.This study made use of the SPI values to identify droughts at three and twelve months time scale. Extreme drought years were also identified for both the basins over the study period considered. Indices value obtained from grid point precipitation data were interpolated over the whole area using spatial interpolation technique in QGIS software in order to obtain areal extension of the drought severity. The results indicated that over Godavari basin, extreme drought was observed in the year 1971,2003 and 2010. Mann Kendall test and Sen’s Slope showed decreasing trend over the North-West area of the basin. Over Beas basin, extreme drought was observed in the year 1972 and 2002. Month of April and May received the least rainfall and negative trend was observed by Mann Kendall test and Sen’s Slope over the North and Central part of the basin. Overall outcome indicates that time to time droughts have been affecting Godavari Basin and decreasing trend indicates more extreme droughts in future , same is expected in some areas of Beas Basin and this would lead to unfavourable effect on water resources of both the areas.