Summary:

Commonly applied in Poland, the Błaszczyk equation of 1954 for design rainfall is based on not quite reliable data and the approach presented therein raises serious doubts concerning the correctness of the method. Of course, not only the scarcity of the then data bases should be taken into account, but also computational difficulties existing in those years. However, independently of these problems, there was no rationale for accepting 67 years as the length of the observation series when the actual number of observation years was 37. As a consequence, the resulting design rainfall intensities for given exceedance probabilities were lower than the values that would be obtained if the correct length of the observation series had been adopted. There is also second critical point of the discussed method: the estimation procedure of the model parameter is incompatible with that presented in the paper and, moreover, is clearly erroneous.