RAINFALL CHANGING TREND ANALYSIS (CASE STUDY: BALI ISLAND)

• Main Author: Rosdiana, Rosa
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/67840
• Institution: Institut Teknologi Bandung

The evidence of climate change impacts has been systematically reported by the Intergovermental Panel on Climate Change (IPCC). Climate change has a direct impact on the hydrological cycle, for example, an increase in rainfall. Increased rainfall can be the cause of flooding, as water infrastructure such as existing drainage cannot accommodate the magnitude of runoff, hence flooding events due to extreme rainfall increase. Flood prevention efforts need to be developed, not only focusing on physical efforts, but also data which up to date for analysis. This study discusses the comparison of rainfall trends in Bali that occurred in the previous period with the current period as an indication of the influence of climate change on hydrological analysis. The rainfall comparison was carried out by evaluating the 2,5,10, and 20 year return period of design rainfall in Bali in terms of the period and the amount of historical data that used (1993-2019) and analyzing the trend of heavy rain events. The analysis method was carried out by dividing 2 analysis periods, there are the previous 20 years (1993-2012) and the current 20 years (2000-2019). This study uses rainfall data for 6 Rain Stations, they are Bongancina Station, Dauh Waru Station, Gadungan Station, Gitgit Station, Negara Station, and Susuan Station. The results of the analysis showed that there is an increase of design rainfall from the previous period (1993-2012) to the current period (2000-2019) at 5 rain stations, that are Bongancina Station, Gadungan Station, Gitgit Station, Negara Station and Susuan Station. The average of increase rainfall for 2,5,10, and 20 year return period respectively are 10.32%; 10.73%; 19.54%; and 21.32%. While the number of events of heavy rain is increasing unevenly. There are 2 stations that have increase in the number of heavy rain events from the previous period to the recent period, they are Negara Station and Gitgit Station. At Gitgit station there is an increase of 1.24 times or about 24% more frequently, while at the Negara Station the increase is 1.6 times or about 16% more frequently from previous period to lates period at a cumulative annual rainfall of 2,500 mm (comparison= 1.0).