SERVIR-Himalaya Small Grant Programme

Upgrading satellite-based flood forecasting with near real-time Jason-2 satellite altimeter data

The Institute of Water Modeling (IWM) in Bangladesh will conduct research to test the performance of a flood forecasting methodology that is based on JASON-2 Satellite Altimeter data and HEC-GeoRAS modeling software. The research will draw a connection between the water level measured at Bahadurabad and Hardinge bridge, and the water levels measured further upstream in India. Water level in the Indian territory would be estimated on the basis of JASON-2 altimetry data. The JASON-2 satellite provides water level data at several locations along the Ganges and the Brahmaputra basin. 

Bangladesh is extremely vulnerable to natural disasters due to its geo-physical location. Huge cross-border inflows, low-lying topography, and deposition of sediment in the rivers have made Bangladesh highly vulnerable to flood. Flood forecasting is an important tool for reducing the damage of 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 in near real-time and the absence of a data sharing treaty among the trans-boundary nations. Bangladesh occupies approximately 7% of the total area of the Ganges, Brahmaputra and Meghna basin. More than 90% of the drainage flows are generated beyond the boundary where the hydrological data are controlled by India, Nepal and Bhutan. 

The accuracy of forecasts emerging from a hydrological model could be compromised without prior knowledge of day-to-day flow regulation at different locations upstream of Bangladesh. Only satellite altimeter monitoring allows us to identify the actual river levels upstream that reflect the human intervention at that location. This is critical for accurate downstream forecasts. 

The research seeks to generate water level data for up to 8 days lead time. The data gathered from Bahadurad and Harding Bridge can be used as boundary conditions for simulation of water level at 12 locations inside Bangladesh, mostly in the Ganges and the Brahmaputra rivers. Forecasts of river water level, along with flood maps and flood bulletins prepared for the research, will be disseminated both through a geo-spatial web portal and during stakeholder meetings for feedback.  

A half-day stakeholder consultation workshop was held on 23 August 2014 to share the study objectives, study methodology and anticipated outcome of the research with concerned professionals in water and flood disaster management in Bangladesh.