Assessing the Impact of Climate Change on Irrigation Water Needs Through Conjunctive Water Use: Future Prospectives

Over the past two decades, climate change and climatic variability have received significant attention from the scientific community. The present study investigates the impact of future climate change on irrigation water requirements in the coastal districts of Odisha, Eastern India, specifically within the Phulnakhara distributary’s command area of the main Puri canal system. Field investigations were conducted during the kharif and rabi seasons of 2019–2020 and 2020–2021. The study offers a new perspective involving a future climate data-driven model with water requirements of RCP 4.5 for this canal command area, and after integrating this with the optimal cropping area, the optimal future irrigation water needs for the kharif and rabi seasons were determined. The study focused on assessing future irrigation water demands under changing climatic conditions, with an emphasis on the conjunctive use of surface and groundwater resources. Projections indicate that peak irrigation demand will occur in the kharif season of 2042–2043 and the rabi season of 2044–2045. Furthermore, a significant decline in groundwater levels is anticipated, ranging from 1.23 to 1.42 m below ground level (BGL) during the kharif season and from 1.46 to 1.64 m BGL during the rabi season, over the next 30 years (2021–2022 to 2050–2051). The most pronounced groundwater table decline is projected for the years 2042–2043 (kharif) and 2044–2045 (rabi), highlighting the need for sustainable water resource management strategies in the region. Based on this study, integrating the optimal crop area with future irrigation water needs will result in groundwater table fluctuations under the permissible limit.