Mekong bursts banks at Laotian capital, Vientiane

On 14 August 2008, the Mekong River burst its banks at Vientiane, the capital city of Laos, on the border with Thailand. The SPOT 5 satellite identifies the flooded areas.

Torrential rain caused an exceptional rise in the water level on the Mekong River, which forms the border between Laos and Thailand. On 14 August 2008, large parts of the Laotian capital of Vientiane came under water, along with surrounding farmland. The heavy rain also affected Cambodia and Vietnam.

In order to allocate emergency services to the inhabitants of the capital and surrounding areas that need them most, logisticians in civil protection and humanitarian aid need rapid mapping to help them locate the affected areas and assess the river’s behaviour.

Two SPOT 5 scenes were delivered under the International Charter on Space & Major Disasters: an archive image acquired on 29 January 2007 and a tasked image acquired on 22 August 2008.

Rapid mapping provides emergency logisticians with the vital information they need.

Spot Image presents three examples of rapid mapping information derived from the two SPOT 5 satellite images of the Mekong:

• the impact of flooding in agricultural areas,
• changes in river width,
• river flow rate.

To assess the impact of the rising water level on the river banks, the satellite images are fed into a geographic information system (GIS) and measurements of river width made on the two images.

The wake effect caused by the pillars of the bridge that links Laos and Thailand are evidence of just how fast the river is flowing, making any significant routine navigation impossible.