Effect of changes in climate variables on hydrological regime of Chenab basin, western Himalaya

Sonia Grover,Shresth Tayal,Stein Beldring,Richa Sharma

doi:10.2166/wcc.2021.003

Abstract

Abstract In high altitude, scarcely gauged basins, climate change impact assessment on river discharge is important for sustainable management of water resources. These basins are sources for irrigation and hydropower generation in the region. Expected changes in precipitation and temperature can affect the basin's hydrological regime which will have consequential impacts on the dependent sectors. For quantifying the impacts of major climatic variables on hydrological processes, this paper examined bias-corrected GCM outputs coupled with a hydrological model – HBV for Chenab basin. Trend analysis shows that precipitation would decrease after the short-term period and temperature is expected to increase throughout the century. Simulated river discharge is expected to increase throughout the 21st century under both RCP 4.5 and RCP 8.5 scenarios. It is also observed that there would be a shift in seasonal discharge patterns with increased pre- and post-monsoon contributions. Increase in snow and ice melt contribution to the overall discharge is also expected and would range between 50 and 59% until 2100. This study concluded that expected increase in discharge volume coupled with shift in seasonal discharge pattern would impact the basin water management and thus it is important to consider the impact of climate change on the hydrological regimes of basins.

Highlights

Increasing surface temperature and variable precipitation patterns are likely to occur over the century and the impacts of climate change are of major concern worldwide (Bajracharya et al )
Basins which have a significant contribution from snow and ice melt are more vulnerable to an increase in surface temperature (Jeelani et al ) and these changes will impact the hydrological regime by affecting the timing and volume of river discharge in the region (Uprety et al )
This study aims to assess the impacts of climate change on the hydrological regime of Chenab basin which is one of the westward flowing tributaries of the Indus basin

Summary

Introduction

Increasing surface temperature and variable precipitation patterns are likely to occur over the century and the impacts of climate change are of major concern worldwide (Bajracharya et al ). Some studies have reported spatial variation in the rate of warming and precipitation dynamics within the Himalayas (Immerzeel et al ; Pandey ) This has been linked to the melt characteristics of the glaciers in the region and to the water availability (Harper & Humphrey ; Kääb et al ; Pritchard ). Basins which have a significant contribution from snow and ice melt are more vulnerable to an increase in surface temperature (Jeelani et al ) and these changes will impact the hydrological regime by affecting the timing and volume of river discharge in the region (Uprety et al ). It is imperative to understand the potential impacts of climate change on the hydrological regime of the basins in the Himalayan region for sustainable water resources management. The Indus basin, which sustains the lives of millions of people, requires proper planning and management of water resources with due consideration of climate change (Lutz et al )

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Conclusion