Climate change impacts on irrigated rice and wheat production in Gomti River basin of India: a case study

Potential future impacts of climate change on irrigated rice and wheat production and their evapotranspiration and irrigation requirements in the Gomti River basin were assessed by integrating a widely used hydrological model "Soil and Water Assessment Tool (SWAT)" and climate change scenario generated from MIROC (HiRes) global climate model. SWAT model was calibrated and validated using monthly streamflow data of four spatially distributed gauging stations and district wise wheat and rice yields data for the districts located within the basin. Simulation results showed an increase in mean annual rice yield in the range of 5.5-6.7, 16.6-20.2 and 26-33.4 % during 2020s, 2050s and 2080s, respectively. Similarly, mean annual wheat yield is also likely to increase by 13.9-15.4, 23.6-25.6 and 25.2-27.9 % for the same future time periods. Evapotranspiration for both wheat and rice is projected to increase in the range of 3-9.6 and 7.8-16.3 %, respectively. With increase in rainfall during rice growing season, irrigation water allocation for rice is likely to decrease (<5 %) in future periods, but irrigation water allocation for wheat is likely to increase by 17.0-45.3 % in future periods.