Drought Severity Assessment in Arid Area of Thal Doab using Remote Sensing and GIS

Abstract

Thal Doab, which is situated between rivers Indus, Jhelum and Chenab, bears extremely dry weather conditions with very low rainfall. Gram is the most important Rabi crop sown in this region. During drought period, the production of this crop is affected badly. Globally there are four known categories of drought i.e. Meteorological, Agricultural, Hydrological and Socio-economic. In this study meteorological and agricultural parameters were analyzed for the variety of data for the years i.e. 1989, 1995, 2001 and 2007. Initially anomalies were calculated for NDVI, rainfall and crop yield to evaluate percent change in different years. Crop yield and NDVI possess negative anomalies during drought years while in case of non-drought years, static and positive anomalies were found. Then Standardized Precipitation Index was computed on six monthly bases for the time series of nineteen years (1989-2007). The correlation regression analysis was preformed to identify the dependency level among different parameters. Positive correlation was found between SPI, NDVI, rainfall anomalies, crop yield, NDVI anomalies, and total seasonal rainfall. Similarly ETo was also calculated from the data. Negative correlation between crop yield and ETo was observed. The weighted overlay analysis method was also applied by assigning relative ranks to each factor. The meteorological and agricultural drought was assessed by overlaying SPI, Rainfall anomalies, ETo , crop yield, NDVI anomalies, and water table depth data. The well known 2001 drought year was confined by using above method applied in this research. Finally drought severity maps were generated by integrating the meteorological and agricultural drought severity maps, indicating the areas facing combine hazard condition. The maps can be extremely helpful to the planners to reveal the situation in the area.