Study of rain pattern and rain characteristics on design flood discharge as the impact of climate change

Abstract

Climate change brings changes to the characteristics of rain and rain patterns so that it affects the flow of rivers. This study aims to determine the effect of climate change on river flood discharge by paying attention to rain patterns and rain characteristics. This research was conducted in the Bangga watershed, Indonesia. The methods used include Makesens, statistical standard deviation, Oldeman, Log Pearson III, and HSS Nakayasu. The data used is daily rainfall data for 29 years from Bangga Atas and Bangga Bawah stations. The results of this study are: the rain pattern for the last 10 years (2012-2021) remains the same as the previous 19 years (1993)(1994)(1995)(1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011), namely Pattern B or Equatorial Pattern. Rainfall characteristics and climate change show an upward trend for the last 10 years compared to the previous 19 years. The design flood discharge for the last 10 years is greater than the previous 19 years for the 1.01 return period; 2; 5 years. Meanwhile, at other times the results are smaller. It can be concluded, that although there has been an increasing trend of rainfall in the last 10 years, it has not caused an increase in the design flood discharge for all return periods.