This session concerns
measurements and estimations of water levels, water
extent, water storage and water discharge of surface water
bodies, such as rivers, lakes, floodplains and wetlands,
as well as groundwater, through the combined use of remote
sensing and in situ measurements. Contributions that also
cover aspects on assimilation of remote sensing together
with in situ data within hydrodynamic models are welcome
and encouraged.
The monitoring of river water levels, river discharges,
water bodies extent, storage in lakes and reservoirs, and
floodplain dynamics plays a key role in assessing water
resources, understanding surface water dynamics,
characterising and mitigating water related risks and
enabling integrated management of water resources and
aquatic ecosystems.
While in situ measurement networks play a central role in
the monitoring effort, remote sensing techniques are
contributing by providing near real time measurements as
well as long homogeneous time series to study the impact
of climate change, over various scales from local to
regional and global.
During the past thirty years 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 and 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 still challenging with available space borne
techniques. Interferometric Synthetic Aperture Radar
(InSAR) is also now commonly used to understand wetland
sheet flow, floodplain dynamics and surface water level
changes, with more complex stacking processes to study the
relationship between ground deformation and changes in
groundwater resources.
Traditional instruments contribute to long-term water
level monitoring and provide baseline databases.
Scientific applications of more complex technologies like
the SAR altimetry on CryoSat-2 and Sentinel-3A/B missions
are maturing. The future SWOT mission, to be launched in
2021, will open up many new hydrology-related
opportunities.