Author(s): Dwi Jokowinarno; Dyah Indriana Kusumastuti

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Keywords: Rainfall intensity; IDF curve; Length of data

Abstract: IDF Curve is significant for determining the rainfall intensity of design rainfall in calculating design flood which is crucial in designing hydrologic structures. The intensity of design rainfall is determined by rainfall data used. This study aims to analyse the effect of the length of rainfall data on IDF curve. This is done by comparing IDF curve developed from the entire rainfall data set to some part of rainfall data set. This study used rainfall data collected from automatic rainfall recorder of BMG Radin Inten II Station and from geophysics station Kotabumi. Rainfall data from BMG Radin Inten II Station are grouped into several data sets with data lengths of 4, 6, 8 and 10 years. While rainfall data from station Kotabumi is also grouped into several data sets with data lengths of 5, 7, 9, 11 and 13 years. All the data sets were analysed to determine the IDF curve for return periods of 2, 5, 10, 25, 50 and 100 years. This study shows that rainfall intensities of design rainfalls as expressed in IDF curves from BMG Radin Inten II station are higher compared to those from geophysics station of Kotabumi. In addition, IDF curve developed using longer rainfall data tends to be more stable and reflects possible rainfall events.

DOI:

Year: 2018