Computer‐oriented Wilson‐Hilferty transformation that preserves the first three moments and the lower bound of the Pearson type 3 distribution

The modification in this paper of the familiar Wilson‐Hilferty transformation has exactly the same mean, variance, skew, and lower bound as the Pearson type 3 variate that it is intended to approximate. Although the original Wilson‐Hilferty approximation is adequate only at skews of less than about 3.0, the new one remains satisfactory throughout the range of hydrologic interest.