Rainfall intensity-frequency-duration relationship for Solapur in scarcity zone of Maharashtra

The characteristics of rainfall, viz., intensity, duration, frequency of rainfall, time distribution and geographical distribution are responsible for producing runoff. Rainfall intensity-frequency-duration equations are required for design of soil and water conservation and runoff disposal structures and for planning flood control projects. The rainfall intensity-duration-return period relationship as I = (KT^a) / (t+b)^d has been developed for Solapur region under scarcity zone of Maharashtra. The constants K, a, b and d in this equation are location specific. The values of parameters a and b were determined by using graphical method and the values of K and d by least squares method. The daily automatic rain gauge charts of Solapur were analyzed in the form of annual maximum series of various durations, viz. 5, 10, 15, 30 minutes, 1, 3, 6, 12 and 24 hours. The constants K, a, b and d for Solapur were found earlier as 11.08 0.1892, 1.01 and 1.2066 respectively by analyzing 17 years daily automatic rain gauge charts of Solapur. These constants K, a, b and d were now modified to 4.57, 0.1934, 0.40 and 0.9187 respectively by analyzing 37 years (1970 to 2020 except 1973, 1978, 1983-1988, 1992, 1993, 1997-2000) daily automatic rain gauge charts. The modified constants will be helpful in design of runoff disposal structures in the Solapur region.