This session focuses on the hydrogeodetic measurement of water bodies such as rivers, lakes, reservoirs, floodplains, wetlands, and groundwater. The measurements relate to estimating water levels, extent, storage, discharge and runoff through the combined use of remote sensing and in situ observations, and their assimilation in numerical models, data-driven and machine learning approaches, leading to both hindcasts and forecasts.
Detailed monitoring of water bodies plays a key role in assessing water resources, understanding water dynamics, characterising and mitigating water-related risks and enabling integrated and sustainable water resources management of aquatic ecosystems. While in situ measurement networks play a central role in the monitoring effort, remote sensing techniques provide homogeneous spatiotemporal measurements in near real-time with great spatial coverage and long time series. The combined use of in situ observations, remote sensing, machine learning approaches, and numerical modelling can provide new insights into the impact of climate change on water bodies from local to regional and global scales.

During the past three decades, a large number of satellites and sensors has been developed and launched, allowing to quantify and monitor the extent of open water bodies (passive and active microwave, optical), the water levels (radar/laser altimetry), the global water storage and its changes (variable gravity). River discharge, a key variable of hydrological dynamics, can be estimated by combining space/in situ observations and modelling, although it remains still challenging with available spaceborne techniques, particularly in poorly gauged and ungauged regions. Additionally, we welcome studies developing multi-mission integration, data fusion, uncertainty characterisation, calibration and validation, data assimilation, machine learning, and forecasting approaches for water body applications. Interferometric Synthetic Aperture Radar (InSAR) is also commonly used to understand wetland connectivity, floodplain dynamics and surface water level and extent changes.

We also welcome submissions on maturing recent technologies like fully-focused SAR Altimetry, and on the growing exploitation of SWOT observations, providing remarkable hydrology-related opportunities, as well as submissions of pre-launch studies for CRISTAL, Sentinel-3C/3D/3NG/6NG, MAGIC/NGGM, Guanlan, HY-2 and SmallSat constellations e.g., the SMASH concept now called REVALTO.