Analisis Curah Hujan untuk Pendugaan Debit Puncak dengan Metode Rasional pada Das Belawan Kabupaten Deli Serdang

Abstract

Rainfall is the most important input component in the hydrologic process. Some of rainfall characteristics, are intensity (I), duration (t), depth (d) and frequency. Intensity that is related to duration and frequency can be expressed by intensity duration frequency (IDF) curve. IDF curve can be used to calculated floodrate using rational method. In this IDF study, daily rainfall depth was calculated by frequency analysis, which was started by determining the daily maximum mean rainfall, in this case there are three stations were observed at DAS Belawan i.e Bulu Cina, Tandem Hilir and Sei Semayang, then followed by calculating statistical parameter to choose the best distribution. Intensity could be calculated by mononobe method, while coefficient of runoff value was taken from land use data at DAS Belawan. The result of this study indicated that most data was fixed to the log Pearson Type III distribution.