531 / 2024-06-30 20:21:42

Evaluating Variations in Hydroclimatic indices over the upper regions of the Indus River Basin

Chenab river basin; Climate indices; Hydroclimatic extreme; Cimpact2; Indicator of hydrological alteration

Subtheme 5: Climate Change: Adaptation, Mitigation and Resilience > Topic 1: Hydrology and Water Resources response to climate change

Climate change and variability have a substantial impact on hydroclimatic extremes, including droughts and floods, which affect ecosystems, human lives, and livelihoods. We are examining the enduring patterns in these extreme situations.  Climpact2 and IHA software  used to evaluate extreme hydroclimatic indices in the Chenab River Basin, which is part of the upper Indus River Basin. The analysis contains daily precipitation and temperature data from 1980 to 2023, discharge data from 2010 to 2014, twelve temperature indices, and eight precipitation indices. The results show decline in the RX1day and RX5day indices of 0.002 and 0.04 units, respectively. Threshold indices (R10, R20, and R25) and percentile-based indices (R95, R99) are likewise trending downward. Conversely, the SDII index  increased by 3.02 units per year. The PRCPTOT index reached its peak in the early 1980s and late 2010s. The CDD trends declining, indicating  extended dry spells ,warm days (TX90p) are increasing, while cold nights (TN10p) and cold days (TX10p) are decreasing. Hot days are becoming more prevalent (TR20 and SU25 indices), and the warm spell duration index (WSDI) is rising, whereas the cold spell duration index (CSDI) is declining by 0.12 units each year. Significant variability and a drop in median flow, particularly during the monsoon, are evident in hydrological trends, demonstrating a strong correlation with seasonal precipitation. According to this study, the Chenab River Basin displays reducing precipitation patterns, significant temperature variations, and moderate to high flow regime variability. To mitigate damages and maintain basin development, effective management and adaptation are essential.