ABSTRACT: How much water is there and when will it become available? These are the questions most water managers, like hydropower operators or water utilities, are asking to comply with water supply. The water discharge in a river is the result of a complex hydrological balance that starts in the upper part of the catchment and continues downstream: precipitation, snow melting, evapotranspiration, infiltration, and runoff are all processes that contribute to water availability. With climate change, current prediction procedures, often based purely on historical data, are incapable of following the new climatic trend. A new approach based on satellite imageries, physical models and machine learning is getting the edge in the market, with higher accuracy and a global reach: the Digital Twin aims to digitize processes in order to be replicated in a virtual concept, to better monitor water availability and forecast its evolution. BIO #1: Matteo Dall'Amico is the founder of MobyGIS. Management engineer by training, in 2010 he obtained a Ph.D. in Environmental Engineering with a specialization in hydrology and snow modeling. He is the author of publications in scientific journals and has contributed to the development of hydrological models in Italy and abroad. He has more than 15 years of experience in monitoring and forecasting services for water in favor of the hydroelectric sectors, municipal utilities of the water cycle, and civil protection. BIO #2: Stefano Tasin is an environmental engineer and is the CTO of MobyGIS. After graduating, he collaborated with the University of Trento in the development of hydrological models and the management of meteorological databases. He has solid skills in Python, R, C++, bash, awk, and in advanced management of structured and unstructured databases. Since 2017 he has been working at MobyGIS, where he is responsible for the IT infrastructure, model development, and data flow.