Impacts of drought on surface water storage in India

Water bodies such as lakes and reservoirs are essential components of the hydrological cycle, providing water for agriculture, domestic use, industry, and supporting biodiversity and energy production. In India, especially in arid and semi-arid regions, these water bodies serve as vital lifelines by storing monsoon precipitation and ensuring year-round water availability. Despite their importance, the large-scale impact of drought on Indian water bodies has not been thoroughly explored. This study examines spatio-temporal variations in water area and quantifies the impacts of drought using remotely sensed data from Landsat satellites (4, 5, 7, and 8) and climate variables from 1990 to 2018. The results indicate that 35% of water bodies show significant declining trends, with average reductions of 10% in the long-term mean maximum area and 5% in the minimum area. The decline in water area is most pronounced during droughts, severely affecting small water bodies that shrink more rapidly than medium and large ones. Moreover, the duration of a 20% reduction in water area decreases by 1 month during drought periods. The findings reveal that combined monsoon and post-monsoon droughts have significantly impacted water areas, particularly in central and southern India. Therefore, the rapidly shrinking water bodies identified in this study can contribute to improved water resource management by enabling the development of an early warning system in India.