Probabilistic Modelling of Hourly Rainfall Data for Development of Intensity-Duration-Frequency Relationships

The rainfall Intensity-Duration-Frequency (IDF) relationship is commonly required for planning and designing of various water resources projects. The IDF relationship is a mathematical relationship between the rainfall intensity, duration and return period. This relationship is determined through statistical analysis of recorded rainfall data. In this paper, annual n-hourly maximum rainfall for different duration of 'n' such as 1-hour (hr), 2-hr, 3-hr, 6-hr, 12-hr, 18-hr, 24-hr, 48-hr and 72-hr are extracted from hourly rainfall data recorded at Kalingapatnam and Hissar; and further used for estimation of rainfall for different return periods. Order statistics approach is applied for determination of estimators of Gumbel distribution. Regional IDF relationships to estimate rainfall intensity for different return periods for Hissar and Kalingapatnam regions are developed and presented in the paper.