ASSESSING VULNERABILITY TO EXTREME RAINFALL EVENTS IN THE NORTH-EASTERN PART OF CENTRAL JAVA

Fitria Nucifera, Dr. M.Pramono Hadi, M.Sc.

2013 | Tesis | S2 Geografi

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Extreme rainfall event naturally occurs in the climate system. However, in the last decade frequency and intensity of extreme rainfall events has been increased. Extreme rainfall events frequently triggered some disasters such as flood and landslide. Most of extreme events occurred in the last decade in Indonesia are wet extreme events. Hence, this research will be focused on wet extreme events. North-eastern part of Central Java frequently suffers flooding due to extreme rainfall events. It is important to assess the vulnerability to rainfall extreme events in this area. The objectives of this research are: 1) to identify spatial and temporal distribution of extreme rainfall events; 2) to identify the spatial distribution of levels of vulnerability to rainfall extreme events. Main data of this research is daily rainfall from rainfall stations around research area. Extreme rainfall events will be determined from the data series. This research considers using 10 years data (2001 – 2010) for describing climate condition regarding the available data. Extreme rainfall event indices from WMO (2009) and BMKG (2010) have been used for defining extreme rainfall events in this research. Spatial distribution of extreme rainfall events can be mapped using spatial interpolation method. Mann-Kendal test method used to identify temporal trend of extreme rainfall events. Extreme rainfall events data can be synchronized with disaster events database. Vulnerability index was composed by combining exposure, sensitivity and adaptive capacity parameter. Index was generated in SPSS software. High frequency of rainfall extreme events occurred in the northern slope of Muria Mountain and in the middle part of Semarang. Low frequency of rainfall extreme events occurred in the eastern slope of Muria Mountain. It is influenced by topography and wind circulation around research area. Rainfall extreme event is tends to decrease in high amount of daily rainfall (> 100 mm). Whereas rainfall is tends to increase in small amount of daily rainfall (< 100 mm). Most of research area is classified into low level of vulnerability to rainfall extreme events. Level of vulnerability is influenced by biophysical and socioeconomic factors. Disaster which occurred in research area such as flood is not directly influenced by extreme rainfall events in this area itself. Flood occurred due to contribution of extreme rainfall events in the upper part of watershed that is located outside research area.

Kata Kunci : extreme rainfall events, spatial distribution, temporal distribution, vulnerability