Developing rainfall intensity-duration-frequency relationship for Hyderabad city in India

Abstract

Accurate andcurrent rainfall characterization is an important tool for water related system design. The intensity, duration, and frequency relationship (IDF) of rainfall occurrence can be done through regular records of hourly rainfall data. The objective of this study is to generate the intensity-duration-frequency relationships of precipitation, using the method of Gumbel theory of distribution and Log Pearson type III distribution. The data set are used from gage in Hyderabad city, the capital of Andhara Pradesh: hourly rainfall data for the 19 years from 1993-2011. Hourly data is used to develop updated IDF relationships. IDF curves were prepare for return periods of 2, 5, 10, 25, 50, and 100 years for 1-, 2-, 4-, 8-, and 24 hour durations. The updated IDF relationship definitely show a huge change in rainfall characteristics compared with other older relationships for the area surrounding Hyderabad, India. The result obtained showed that in all the cases the rainfall intensities obtained using Gumbel distribution are slightly than the results obtained using the LPT III distribution.