South Africa - Inkaba.org

New tools for hydrologic research at Sutherland Observatory,
western Karoo: superconducting gravimetry and satellite
gravimetry
A. Güntner, Ch. Förste
GFZ German Research Centre for Geosciences, Telegrafenberg, Potsdam, Germany, andreas.güntner@gfzpotsdam.de
ABSTRACT
The existence of water and its distribution are of major importance for the environmental well-being and
economical prosperity of a region. Semi-arid areas such as the western Karoo depend on the availability of
groundwater. Therefore it is of essential interest to gain comprehensive information on the groundwater recharge
and discharge. The goal of this project is to improve the understanding of hydrological processes in the western
Karoo on different spatial and temporal scales by deploying gravity observations and gravimetric/hydrological
modelling. Investigation of the interrelation between hydrology and geodesy is done by the following worksteps:
(1) a 4-D simulation of the influence of water storage changes on the superconducting gravimeter installed at the
Sutherland Observatory SAGOS, (2) measuring and modelling of the water storages at the Sutherland site; namely
groundwater, soil moisture and snow, (3) transformation of the changes in water storage to a gravimetric signal,
and (4) comparison between the measured gravity change by the SG and the estimated hydrological gravity
response.
On a regional scale, the hydrological effects on gravity can be assessed by comparison of GRACE satellite gravity
data with regional-scale hydrological models that integrate information from the small-scale monitoring and
modelling at the Sutherland and other test sites. The results will help for an improved local and regional
quantification of hydrological dynamics and thus establish additional means for the management of the valuable
resource water.
KEYWORDS: Hydrology, superconducting gravimeter, GRACE, groundwater management
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