Abstract
Power transformation was used to normalize the peak daily and peak monthly rainfall at various raingage stations in Iraq. Excellent correlations were found between the coefficient of skewness (Cs) and a parameter for power transformation (λ), coefficient of kurtosis (Ck) and λ, and between Cs and Ck. The relationship between Cs and λ is used to develop an estimation procedure for calculation of the transformation parameter. The method eliminates the use of trial and error for estimating λ. The method has been used for estimating T-year peak daily and peak monthly rainfall by power transformation. The results are compared with results from other methods.