The Influences of Precipitations Variability in the Surface Runoff of Hanábana Catchment, Main Contributor of the Largest Wetland in Cuba

Abstract

The purpose of the paper is to show the surface runoff impacts due to variability of rainfall. Hanábana catchment is the main contributor of the Zapata West Wetland, for which a variation in the precipitations would affect the largest Wetland in Cuba directly where the main problem is the water imbalance. The rainfall time series of 78 years (1931–2008) was statistically analyzed to determine the precipitation variability. Three periods were detected in the time evolution of the rainfall, 1931–1960, 1961–1980 and 1981–2008. The first two periods show a growing tendency and the difference between both is not significant. The average of every period corresponds to a probability of means and wet means years, with 36% and 42%, respectively. The period 1981–2008 shows a falling tendency of dry characteristics $\left( {\mathrm{ p}=63\%} \right)$ that could extend up to 2025. The variability of the precipitations to the local scale of the catchment does not coincide with the established periods to global scale for the WMO. The correlation between the runoff and the rainfall demonstrated an average decrease of 10% of the volume of the contribution toward the Wetland of Zapata.