Assessment of spatio-temporal trend in hydro-climatic variables and their agricultural implications in the Mahanadi River Basin using innovative trend analysis technique

Climate change and its effects on hydro-climatic parameters have become a major concern for water resource management in India. This study provides a comprehensive assessment of long-term (1980-2024) hydro-climatic variability in the Mahanadi River Basin (MRB) using the robust Innovative Trend Analysis (ITA) technique. Trends in rainfall, streamflow, maximum temperature (Tmax) and minimum temperature (Tmin) were analyzed on season-wise (summer, monsoon, post-monsoon and winter) and annually for the entire basin as well as for its upper, middle and lower sub-basins. The results revealed a complex trend: annually, 48.3 % of stations showed increasing rainfall with significant spatial divergence. The upper sub-basin experienced a clear wetting trend (66.7 % of stations showing increase), while the middle sub-basin faced a significant declining trend of rainfall (57.3 % of stations showing decrease). However, streamflow exhibited a consistent decreasing trend at 60 % of gauging stations throughout the basin and at more than 80 % of stations in the upper and middle sub-basins, even having positive rainfall trend. Tmax showed a uniform increasing trend at all of the stations, while Tmin trends varied, leading to a widening diurnal temperature range. These findings confirm that increasing evapotranspiration, driven by global warming, has become a key factor influencing water availability in the basin. Hence, site specific water conservation measures are urgently required particularly in the upper and middle sub-basins to build resilience against growing climatic stress. The observed hydro-climatic shifts have already begun to affect the soil moisture dynamics and crop yields across the basin. Therefore, climate-resilient agricultural planning, adoption of drought-tolerant crop varieties, micro-irrigation and rainwater harvesting are essential to sustain agricultural productivity in the Mahanadi basin.