Dry and humid periods constitute one of the climatic phenomena with the greatest impact on hydrology and agricultural activity in the Pampas region of Argentina. In this work, a characterization of drought and wet events for annual periods was made in Azul, Buenos Aires, applying the Moisture Index to the Serial Hydric Balance (BHS). The analysis of the series (1988-2017) confirms a definite trend with consistent results in the three applied methods, which shows a sustained increase in the presence of dry years (negative humidity index). However, when working with decadic periods, the last decade shows a trend break (8 dry years), which was statistically significant between the humidity index (HI) and the two contrasting variables. Finally, the application of the IH was an appropriate tool when analyzing the complexity of droughts and water excess for annual periods, arising from the BHS.

Keywords : Humidity Index, Series Water Balance, Annual Water Situations.