The intergovernmental Group on Earth Observations (GEO) with currently 80 member countries and nearly 50 Participating Organizations, many of them science oriented, is working towards the realization of a coordinated, comprehensive, sustained Earth observation system of systems called the Global Earth Observation System of Systems (GEOSS). The aims is to enable societal benefits of Earth observations, including advances in scientific understanding in the nine Societal Benefit Areas (SBA) Disasters, Health, Energy, Climate, Water, Weather, Ecosystems, Agriculture, and Biodiversity. To realize this vision, GEO's Science and Technology Committee aims to integrate advances in science and technology through appropriate consultation with the research, observation, and application communities; support research efforts necessary for the development of tools required; promote research and development in key areas of Earth sciences to facilitate improvements to Earth observation systems; and encourage and facilitate the transition of systems and techniques from research to operations. This session will focus on the SBA of Water. We invited presentation of examples that show how GEOSS supports and/or benefits from science and technology efforts related to the management of regional to local water resources, including the monitoring, modeling, and prediction of droughts, floods, and resource depletion. In particular, we are looking for presentation that demonstrate the mutual benefits of the involvement of science and technology in GEOSS.