07/08/07

Flood forecasting system could help Bangladesh

Rural flooding in Bangladesh Copyright: Flickr/Jeev

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A new flood forecasting system could help thousands of vulnerable people in flood-prone areas of Bangladesh prepare for disaster.

The system — based at the Georgia Institute of Technology in the United States and jointly developed with the US-based National Center for Atmospheric Research — could deliver up to ten-day forecasts to more than 100,000 people living on floodplains of the Brahmaputra and Ganges rivers.

Discussion with the Bangladesh government about integrating the forecasting system into the country’s existing warning system are ongoing.

Bangladesh — a low-lying delta nation — is one of the world’s most vulnerable regions to floods. Last month (July), floods affected more than half of the country’s districts, leaving millions of people stranded or homeless.

Peter Webster from the Georgia Institute of Technology told SciDev.Net that the forecasting system works in principle.

"We have successfully forecast the floods of 2004 and now the Brahmaputra and Ganges river floods that have occurred during the last few weeks," he said.

Ramasamy Selvaraju, from the Asian Disaster Preparedness Center in Thailand, now based in Bangladesh and involved with the programme, said that local networks were used to communicate the flood warning last month to remote and inaccessible areas.

"[The communities] have indicated that they have planned for their evacuation to embankments and higher land in advance, and stored and transported their minimal assets like food, drinking water, firewood, and clothes during the floods," Selvaraju said.

The programme uses a combination of weather forecast models, satellite data, river gauges, and a new hydrologic modelling technique to predict when the height of major rivers will peak.

Where there is a lack of river gauge data to verify river height, or radar data to detect the intensity of rainfall, the forecasting system compensates with modelling and satellite data.

Selvaraju said the existing warning system in Bangladesh can only predict rising water levels 48–72 hours in advance, so there has been a huge demand from communities — especially those living on remote river islands — for forecasts at least a week in advance so people, particularly farmers, can better prepare.

Most importantly, Selvaraju said, the new forecasting system helps shift from "relief to preparedness".

Webster says they will extend forecasting to 20 days, followed by 1–6 month seasonal forecasts over the next two years. The scheme can be adapted to almost any monsoon nation in Asia, and they hope to extend the system to other Asian countries in the future, he says.