Analysis of rainfall intensity - duration - frequency (IDF) models for design of flood control structures

Rainfall Intensity-Duration-Frequency (IDF) models for duration of 0.50 to 24 h for different design periods were analysed using least squares regression. The first group of models related rainfall intensities to durations, and produced four equations with regression coefficient (R2) ranging from 0.800 to 0.950. The second set of models related rainfall intensities to design periods of 1, 2, 5 and 10 years. The first group of models were com-bined with the second set to produce the general equation of the rainfall intensity, (0.70 ≤ RyxTDTI−=3.72 ≤ 0.88), where x and y represent the physiographic parameters of the catchments producing the runoff, T is design period and D is duration of storms. The physiographic parameters for T = 1, 2, 5 and 10 years were (x, y) = (1.06, 0.64); (1.06, 0.58); (1.06, 0.46); and (1.06, 0.60). The models developed could be used in the design of structures that control storm runoff and flooding. The equations can also be programmed as subroutines in simulation programs. Journal of Applied Science and Technology Vol. 13 (1 & 2) 2008: pp. 104-10