Definition of operational hydrology

As approved in the annex of Resolution 24 of the World Meteorological Congress 2018 (Cg-18), operational Hydrology is the real-time and regular measurement, collection, processing, archiving and distribution of hydrological, hydrometeorological and cryospheric data, and the generation of analyses, models, forecasts and warnings which inform water resources management and support water-related decisions, across a spectrum of temporal and spatial scales. Operational hydrology requires capacity building and scientific and technical advancement and innovation in the areas of observation, data standards and services, modelling, prediction, hydro-informatics and decision support, communications, training, and outreach. 

Annotation: These data include, but are not limited to, precipitation; air temperature and humidity; water level of streams, lakes, deltas and estuaries; streamflow; snow and ice cover, depth and water equivalent; river and lake ice; glacier mass balance; reservoir storage; soil moisture; groundwater and ground frost; evaporation and evapotranspiration; water temperature; sediment dynamics; water and sediment quality and other related variables, including within the context of global change. 

Global change is expressed through different aspects, such as land use changes, socioeconomic dynamics, climate variability and climate change.