Inundation Extents and Volumes of the Congo's Wetlands
Abstract
The estimation of inundation extents and volumes of the Congo's Wetlands involves the need to utilise several different remotely sensed datasets, models, in-situ data and historical maps. In this paper, a combination of in-situ and modelled discharges from a hydrological model, forced by remote sensed data, were used to force a four-kilometre resolution hydrodynamic model. River widths for major rivers were derived from Landsat Imagery, and floodplain channels were digitized using Soviet maps from 1983. Bathymetry and a global friction value were calibrated using a mixture of ERS-2 and Envisat satellite altimetry of water level. The calibrated model simulated channel water surface elevations across the domain with a 0.185 metre bias and a 0.842 metre root mean square error. Downstream Nash-Sutcliffe Efficiency for the gauging station in Kinshasa was 0.84. Inundation extents were compared to the Global Inundation Extent from Multi-Satellites (GIEMS) dataset and volumes changes compared to GRACE. The results show that the hydrodynamic model can reproduce the temporal dynamic of inundation extents and volumes fluctuations. The hydrodynamic model estimate that the average annual variation in water storage change across the model domain is 90 km3. The result also imply that the fluvial process of river-floodplain exchange has a far greater impact than previous studies suggest. Especially for the wetlands centred around the confluence of the Congo and Oubangui rivers, where the GRACE storage anomalies can be accounted for by changes in river volumes and the exchange of water from the river channels to the floodplains.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.H22G..08O
- Keywords:
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- 1819 Geographic Information Systems (GIS);
- HYDROLOGYDE: 1855 Remote sensing;
- HYDROLOGYDE: 1856 River channels;
- HYDROLOGYDE: 1857 Reservoirs (surface);
- HYDROLOGY