Analysis of Rainfall in The Upper Jeneberang River Basin, South Sulawesi, Indonesia

An in-depth understanding of the erratic rainfall patterns in a watershed due to the negative impacts of climate change is crucial to understand the hydrological cycle in a watershed. The main objective is to better understand rainfall trends using statistical tools in the Jeneberang River Basin, South Sulawesi, Indonesia. This study examined rainfall data for 23 years (1996-2019) and collected from three rainfall stations. The nonparametric statistical tests were performed to identify whether there was a positive or negative trend with statistical significance. Results revealed monthly rainfall data for the Alukeke station that there was no significant trend detected in ten months, but May and June indicated a significant trend. This result proved an increasing trend in the data series, though insignificant for the Sen-slope's test. Similarly, the Malino station had a significant level of alpha < 0.05, thereby signifying a trend in the data series. The Sen slope estimator indicated a decreasing trend in February, October, and December, unlike a significantly positive trend in eight months of the seasons. Paladingan rainfall station detected an insignificant trend in the data series, while it recorded a maximum of 1435 mm in December. The sen-slope statistic showed no change in four months of the year as well as a decreasing trend in the other five months. The novelty of this research lies in the theory of value in the analysis of extreme rainfall in the data-scarce Jeneberang watershed. The results are useful for water resources management and disaster risk reduction functions.