The OASIS system allows the monitoring of current hydrological drought conditions and their forecast through the flow anomaly index, which allows the identification of the deficit or excess flow in a given river reach.
For this purpose, the OASIS web portal is a set of hydrological drought maps at the scale of river reaches. Its time scale is one month and the flow forecast is developed for the following month. Its methodology is based on evaluating the monthly flow outputs of the GR2M monthly hydrological model at the scale of the whole of Peru, for which the main input source of the model is the PISCO monthly precipitation product (V2.1). This OASIS web portal is updated on a monthly basis.