An analysis of a rainfall frequency formula as applied to Honduras

Abstract

A precipitation formula for estimating rainfall frequency-duration values from monthly rainfall data in Honduras is compared with frequency-duration values approximated by the Gumbel method. The precipitation formula is empirically developed from rainfall data collected in Central America and from intensities found in a rainfall frequency atlas for the United States. Data from thirty-six precipitation stations scattered throughout Honduras are used in the comparison and the precipitation formula is modified for Honduras conditions. A computer program is developed to make the calculations. The percentage differences between formula derived and Gumbel derived intensities are exponentially distributed. The exponential distribution is used to quantify the differences between the two methods for estimating rainfall intensity. It is concluded that the precipitation formula is useful for determining rainfall frequency-duration values especially in areas where very little precipitation data is available.