Can we supplement in situ data with satellite data?

Water resources management requires the use of hydrometric data mainly from in situ stations. Despite the efforts made to set up and maintain a network of stations (hydrometric or meteorological), water resource managers face various issues (degradation of equipment during floods, vandalism, inaccessibility, lack of financial means for maintenance, etc.). Satellite data can enrich water resources monitoring, whatever the objectives of this monitoring (strategic management of water resources, management of structures, flood and low-water forecasting, etc.). These data have the advantage of covering the whole world, including territories that are difficult to access, in regular time steps. Through several projects, different scientific and industrial partners (IRD, CNES, CLS, CNRS, CENEAU horizontal ellipsis ) have contributed to assess and enhance the use of satellite data for water resources management at the scale of a catchment (e.g. the Amazon) or a territory (Uganda). The objective is to deliver hydrological indicators from the combination of hydrological models, in-situ data and satellite data. This article presents the current possibilities and limitations of using satellite data to optimise the monitoring of water resources.