Spatiotemporal drought assessment of a semi-arid part of middle Tapi River Basin, India

Droughts can be analyzed based on four characteristics: temporal coverage, spatial coverage, intensity, and duration. The impact of drought is more acute in semi-arid regions. The present study covers the spatiotemporal variation of drought related to the semi-arid region of the Tapi River basin in central India. Temporal analysis is conducted using rainfall decile (RD), standardized precipitation index (SPI), and reconnaissance drought index (RDI). Based on the results of temporal analysis, spatial mapping is performed using inverse distance weighted (IDW) method. The streamflow index is computed, to manage the available water resources during severe years of drought. This study also analyzes the existing cropping pattern in the upper Girna basin. Using 34-year data, three severe drought periods in the study region are identified from temporal analysis. Out of the four drought indices used for the present analysis, SPI and RDI have shown the best correlation between the results of temporal and spatial analyses. The streamflow drought index is found to have a gradually decreasing trend in the study area. This shows poor availability of water to the local areas, which in turn leads to drinking water scarcity for livelihood. Based on the study of annual crop yield data, a change in cropping pattern from highly water demanding crops to less water-requirement crops is recommended. The maps prepared using the spatiotemporal analysis will be useful to policymakers and local administrators to take effective measures for drought relief and to plan water resources in the drought-hit regions.