Generation of intensity duration frequency curve using daily rainfall data for aghanashini river watershed, uttara kannada

Abstract

Most of water resource projects are carried out after analysis of rainfall data. Intensity–duration–frequency (IDF) curves are used to analyze the quantity of rainfall of different duration (t) and return periods (T). The study area in Aghanashini watershed lies between 74°18′15.95″ and 74°55′22.84″ E longitude and 14°15′26.21″-14°37′17.65″ N latitude. Area is about 1400.47 km2, and altitude ranges from zero meters to 784 meters above mean sea level. The river extends from Sirsi to Kumta of Uttara Kannada, Karnataka State where it reaches Arabian Sea. The daily rainfall data of nine stations collected from Directorate of Economics and Statistics Bengaluru for years 1998 to 2016 was gone through, and 24-h maximum annual rainfall data was extracted. Indian Meteorological Department (IMD) proposed formula is used to estimate rainfall values for various shorter duration such as 0.083, 0.167, 0.25, 0.5, 1, 2, 12, 24-h. Probability distributions is used to estimate maximum annual rainfall values for various duration (t) and return periods (T) and Chi-square test is carried out to check the best probability distribution. Chi-square test shows that normal distribution is best fit to calculate rainfall intensity (mm/h) for six stations (Balale, Nilkundi, Sirsi, Hittalahally, Tyagali, Katagal), Log-Pearson type III probability distribution is best fit for two stations (Bandal and Siddapur) and Log-Normal distribution for one station, i.e., Kumta in Uttara Kannada. © Springer Nature Singapore Pte Ltd 2021.