The Impact of Climate Change on Discharge in the Winongo Watershed

Abstract

Climate change has become a major problem around the world. One of the impacts of climate change is flooding, regional drought, changes in rainfall characteristics, and climate warming. Watersheds are also called watersheds that function to accommodate, store and drain water that comes from rainfall to lakes or to the sea naturally. Watesheds that are unable to channel water that is rained on will cause flooding. In this study, discharge analysis was conducted in the Winongo watershed using the Nakayasu and Gamma 1 Synthetic Unit Hydrograph (HSS) methods. HSS Nakayasu and Gamma 1 methods are used to analyze hydrographs based on daily rainfall, watershed area and main river length. The results of discharge analysis with HSS Nakayasu and Gamma 1 methods will be correlated with the SPI (Standardized Precipitation Index) value. The discharge calculation for the HSS Nakayasu unit yielded a flow rate of 2.10 m3/second at the 3.32nd hour, whereas the HSS Gamma I recorded a discharge of 1.59 m3/second at the 5.04th hour. The alterations in precipitation within the Winongo watershed exhibit a positive correlation, with maximum rainfall at 116.7 mm in wet condition, and minimum rainfall at 69.80 mm in arid conditions. Climate change influences the periodic discharge in the Winongo watershed, evidenced by an R2 correlation value of 0.4226 with HSS Nakayasu dan 0.4356 with HSS Gama 1, shows a fairly influential relationship of 42.26% or 43.56% of the relationship between SPI and discharge.