Development of Rainfall Intensity-Duration-Frequency (IDF) Curve for some parts of Coastal Region of Karnataka

Abstract

IDF relationship is one of the most commonly used tools in water resources engineering, either for planning, designing and operating of water resource projects against design floods. Due to the variation in rainfall intensity and pattern, it is creating a distress for hydrologic engineers and planners. So, in this project an attempt has been made for the development of IDF relationship for some parts of coastal region of Karnataka. As coastal region is one the flood susceptible area, IDF curves are required for the proper design and planning of urban drainage system and to take initial safety measures against high extreme flood condition. IDF relationship gives the probability of occurrence of extreme rainfall values which is utilized for the proper design of drainage system. The rainfall data is collected from KSNMDC (Karnataka State Natural Disaster Monitoring Centre) department for a period of eight years from 2010 to 2018 for the different rain gauge stations of the coastal regions (Dakshina Kannada, Uttara Kannada and Udupi districts). Using these datasets IDF curves and also an IDF equation is developed in the current study. IDF curves are derived using annual maximum rainfall by Gumbel Extreme Value Distribution, Log Pearson Type III and Empirical method