TREND ANALYSIS OF RAINFALL AND RUNOFF DATA OF PUNPUN RIVER BASIN

The current work is primarily focused with analyzing the shifting rainfall pattern and discharge of a Punpun river basin in Bihar at several raingauge stations, including Patna, Goh, Gurua, Jahanabad, and Nabinagar, using non-parametric statistics. The primary goal is to examine climatic variables, namely precipitation and outflow, in order to examine the rainfall and runoff trends in the basin. The research analysed monthly rainfall and discharge data from 1990 to 2010 to determine the monthly and yearly variance of rainfall and discharge. The same data was then examined to determine the monthly and seasonal variability of rainfall and monthly variability of discharge, for which the Mann-Kendall Test and Sen's slope Estimator were used to determine trend. Monthly and seasonal rainfall and monthly discharge trends have been established here to meet the goal, which has been shown using data from 1990 to 2010. Although trends were detected at several raingauge and discharge stations, the majority of these trends were not statistically significant since p-values were larger than 0.05. It was advised that the availability of data for a longer period of time (more than 21 years) be studied in order to assess trends at raingauge and discharge stations that might provide statistically meaningful findings.