Development of IDF curve under non-stationary meteorological condition

Ankit P Patel, P. V. Timbadiya, P. L. Patel

Friday 3 july 2015

14:45 - 15:00h at Europe 2 (level 0)

Themes: (T) Extreme events, natural variability and climate change, (ST) Flood resilient cities and infrastructures

Parallel session: 16I. Extreme events - Resilient

In the present study, hourly data of rainfall for last 30 years (1983 to 2012) have been used to develop Intensity-Duration-Frequency (IDF) curve for Ahmedabad, Gujarat, India. To assess the effect of non-stationarity in rainfall record and development of IDF for study area, the data are sliced into three equal duration of 10 years, viz. 1983-1992, 1993-2002 and 2003-2012. Further, the IDF curves of each sliced duration are also prepared for different return periods. The derived IDF curves have indicated maximum rainfall intensity, for 5 minute duration and 2-year return period, as 88.83 mm/hr, 103.20 mm/hr and 115.23 mm/hr for 1983-1992, 1993-2002 and 2003-2012 respectively. It is observed that, for all three sliced IDF curve, the maximum intensity increases with time for various duration and frequency. The non–stationarity in the rainfall record is clearly observed as maximum rainfall intensity of a given duration has been found to be in increasing order from IDF curves derived for periods 1983-1992, 1993-2002 and 2003-2012. The analysis presented in the study concludes that non–stationarity in the meteorological data (rainfall) must be taken into account while deriving the IDF curves for designing of storm-water drainage system for urban areas.