Assessment of impact of climate change on streamflow and soil moisture in Pare watershed of Arunachal Pradesh, India

A fragile terrain makes a mountainous watershed like Pare in India's eastern Himalayas extremely sensitive to climate change. However, this watershed has a great deal of potential for the development of water resources; thus, hydrological investigation and impact assessments in light of climate change are essential. Using the soil and water assessment tool (SWAT), the current study examined how discharge and soil moisture in the Pare River of Arunachal Pradesh would change in response to climate change. The projected streamflow was compared with the baseline projection during 1976-2005. The future precipitation scenarios predicted that there will be a decrease in rainy episodes and an increase in dry days in the Pare watershed. This meant that more extreme occurrences would occur in the future. The SWAT model's performances during calibration and validation were deemed satisfactory based on the Nash-Sutcliffe efficiency, p-factor, and r-factor. It was discovered that SWAT slightly underestimated the discharge. The findings revealed that discharge would continue to rise as time progressed from the near to the far-future. Variations in discharge showed shrinkage in high flow days with increased flood amplitude, which might result in major flooding in low-lying areas downstream and significant soil erosion from the upland areas. It was predicted that the surface runoff component would increase significantly in the future, possibly leading to frequent flash floods and soil erosion. However, soil moisture in the Pare watershed would remain more or less the same throughout this century. Even if future streamflow was predicted to rise, worry would always persist due to its unequal distribution. The region's water managers may set guidelines for water and soil conservation measures to cope up with these changes. More studies may be conducted to recommend actions in the study region by local authorities and managers associated with various soil and water sectors.