In recent years, floods in Namibia have impacted hundreds of thousands of people, claiming lives, damaging the built environment, destroying agricultural lands and including consequential challenges like spreading waterborne diseases (i.e. malaria, cholera).
So far, flood extents could not be determined as monitoring from the ground is hampered by inaccessibility of affected areas. Also airborne-based monitoring proved to be challenging because of the cloudy weather conditions. However, the Sentinel-1 radar sensor provides all-weather, day and night cloud-free imagery enabling to acquire the flood extent in spite of bad weather conditions.
On 13th April, Sentinel-1 tuned in over Namibia capturing the flooding in the Caprivi plain from the Zambezi River. The open-source Water Observation and Information System (WOIS) of ESA’s TIGER-NET project (http://www.tiger-net.org), developed by GeoVille and GRAS DHI, was used to process the first S-1 data, extract the water body and create the flood map to be able to assess the flood extent. The data was downloaded and processed by TU-Vienna within less than three hours.
Thus, this monitoring capacity delivered data in near-real time, provided rapid response and supported the Namibian authorities in prioritising and planning emergency issues.
“As part of the good and ongoing cooperation between the Ministry of Agriculture Water and Forestry, National Hydrological Services and the European Space Agency through TIGER-NET, Namibian has been privileged to be one of the first beneficiaries of the Sentinel- 1 satellite that was recently launched by the ESA.”
“The need for reliable and near real-time information is crucial in the field of operational hydrology for flood disaster management and mitigation. The recently launched Sentinel-1 satellite by ESA demonstrated that it has capabilities to acquire satellite data during rainy and difficult weather conditions and to monitor floods in near real time. Sentinel-1 depicted the mass inundation and flooding extent in the eastern floodplains of the Zambezi on 13 April 2014. This demonstrates how the use of satellite data can enhance and supplement operational hydrology in vast areas with limited accessibility and of trans-boundary nature.”
Pauline Mufeti, Head of Hydrological Services Namibia
GeoVille Information Systems GmbH
Sparkassenplatz 2/ 315-325, 6020 Innsbruck, Austria
phone: +43 512 562021 0
DHI GRAS-Geographic Resource Analysis & Science A/S
Geocenter Denmark, Øster Voldgade 10, 1350 Copenhagen K, Denmark
phone: +45 3532 2578