Assessment of low flow trends and change point detection in Mahanadi River basin, India

Low flow in the river is an important parameter that directly impacts on various water management activities. Therefore, the study of long-term low flow records is essential for managing sustainable water resources in a river basin. The impacts of climate change on water resources has shown a significant change in river discharge, making the study of low flow trends and its variability even more crucial. Trends of the various magnitude of low flows such as 1-day min flow, 3-day min flow, 7-day min flow, 30-day min flow, 90-day min flow for 14 stations over Mahanadi River basin India are studied using the Modified Mann Kendall test. Further, the multivariate Bayesian change point analysis has been carried out for detecting the significant change year. The results obtained show an increasing trend in the low flow in the upper part of the Mahanadi River basin as most of the stations. Which are showing a decreasing trend of low flow indices are present in the upper part of the basin. This study concludes the presence of a mixed low flow trend, i.e., increasing, decreasing, and some stations with no trend. From Multivariate Bayesian change point, analysis advocates that there is evidence of some significant change point in all the stations between the period 1995 and 2006. The analysis revealed that the Mahanadi River basin is highly vulnerable to low flow conditions driven by the variability in low flow discharge, which may be linked to an increase in anthropogenic activities in the basin.