Helping flood information reach communities

Experts from IWM
Experts from IWM explain Inundation map to the residents of Kulkandi

Strengthening the capacity of satellite-based flood forecasting using near real time Jason-2 satellite altimeter data under SERVIR-Himalaya Small Grants Programme, ICIMOD

The Institute of Water Modeling (IWM) in Bangladesh has developed a cost-effective information system that provides 8-day flood forecasting. The system provides near real-time information through web GIS with local-level flood forecast maps for flood events. The Jason-2 satellite altimeter data collection system enables the forecasting of trans-boundary flows in downstream countries sharing international river basins. The study was carried out in partnership with the Tennessee Technological University (TTU) and supported by ICIMOD under the SERVIR-Himalaya Initiative’s Small Grants Programme.

Satellite passing path at virtual stations
Satellite passing path at virtual stations
A Set of Regression equations
A Set of Regression equations

Bangladesh’s location makes it extremely vulnerable to natural disasters. Huge cross-border inflows, low-lying topography, and the deposition of sediment in rivers have made Bangladesh highly vulnerable to floods. Flood forecasting is an important tool for reducing damage to existing resources and livestock.

Flood forecasting in the downstream part of any hydrological basin is extremely difficult due to lack of basin-wide hydrological information, unavailability of near real-time data, and the absence of a data sharing treaty among countries sharing trans-boundary basins. Furthermore, the accuracy of forecasts emerging from hydrological models can be compromised if there is no knowledge of the day-to-day flow regulations at different locations upstream of Bangladesh. Only satellite altimeter monitoring allows the identification of actual river levels upstream that reflect the human intervention at that location. Such information is critical for accurate downstream forecasts.

The project used a number of virtual stations, a combination of satellite estimates of water level, and modelling, which provided a forecast of stream flows in Bangladesh. Jason‐2, a joint NASA‐French Satellite mission that measures water levels and provides data relatively promptly (within 24-hours), was used for this purpose. Seven virtual stations at suitable locations along the satellite passing path were selected on the desired river reach.

Inundation maps of Kulkandi
Inundation maps of Kulkandi, Jamalpur district