In Colombia water resources planning and management is supported mainly by technical instruments such as the National Water Assessment Study, which are based on the calculation of several different management indices, estimated solely with in-situ data. In this study we explore the complementarity of two global reanalysis datasets coming from the EartH2Observe project (WFDEI and MSWEP) and the use of rigorous regional and local hydrological modelling for deriving two water management indices,

more »

... e Aridity Index and the Water Regulation Index in the Magdalena-Cauca macrobasin. Results show that the conjunctive use of in-situ data, global reanalysis, and hydrological modelling allows updating the indices calculation more often and that the results are consistent compared to the indices values estimated only with in-situ data. Besides, the methodology implemented has capabilities for being used in scarce data regions and can contribute to assessing uncertainty in the indices estimations.