Development of IDF relationship

Rainfall intensity-duration-frequency relationship and nomographs are required for design of soil and water conservation structures. Rainfall IDF relation is dependent on the physical characteristics of rainfall occurring in a particular place and it vary from location to location. The rainfall IDF relationship can be expressed as, I = K T^a /(t + b )^d Where, I = Maximum rainfall intensity, cm/h T = Return period, years t = Duration, h K, a, b and d = Location specific constants. The study was undertaken to develop the rainfall IDF relationship and station nomographs for Nagpur, Chandrapur, Gadchiroli and Gondia districts and isolines of Vidarbha region. The nomographs were developed for the IDF relationship for the same districts. The method suggested by Luzzadar (1964) was adopted for development of nomographs. Isolines maps for each constant a, b, d and K of Vidarbha region have also been developed.