Contrasting influence of human activities on agricultural and hydrological droughts in India

Human activities associated with intensive irrigation, reservoir storage, and groundwater pumping have substan-tially altered the hydrological cycle, environment, and regional climate in India. However, the role of human ac-tivities on water budget and droughts remains mostly unexplored. We use calibrated and evaluated Community Water Model (CWatM) to quantify the influence of human activities on agricultural (estimated using soil mois-ture) and hydrological (estimated using total runoff) droughts in India during 1951-2016. The simulations using the CWatM were conducted for the Natural (without human influence) and Human (with the human influence of irrigation, reservoir storage, and groundwater pumping) scenarios. Evapotranspiration and soil moisture in-crease while total runoff and groundwater storage decrease under the Human scenario in comparison to the Nat-ural scenario. The dominant influence of human activities on agricultural and hydrological droughts was found during the monsoon and post-monsoon seasons. We find a contrasting effect of human activities on agricultural and hydrological droughts. While human activities reduced the intensity of agricultural droughts, hydrological droughts are intensified under the Human scenario. The intensification of hydrological droughts is linked to ex-cessive water abstraction for irrigation. On the other hand, irrigation increases soil moisture and decreases the intensity of agricultural droughts. Overall, our findings highlight that excessive groundwater pumping and irriga-tion can intensify hydrological droughts, which can have considerable environmental implications. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

The study found that human activities have different effects on agricultural and hydrological droughts in India. While human activities reduced the intensity of agricultural droughts, they intensified hydrological droughts. Excessive groundwater pumping and irrigation may exacerbate hydrological droughts, leading to significant environmental implications.