Bangladesh suffers from major floods on a regular basis of an interval between 8 to 10 years. Existing flood forecasting and warning systems of Bangladesh relies heavily with the information of flood water coming from the upstream countries. About 93 per cent of the catchment areas of the major rivers – the Ganges, the Brahmaputra and the Meghna lies outside the country. Catchment areas distributed between India (64 per cent), China (18 per cent), Nepal (9 per cent), Bangladesh (7 per cent) and Bhutan (3 per cent). Forecasting floods using numerical models such as hydrological and hydrodynamic models require several geospatial and hydro-meteorological data. Geospatial data of the catchment such as river bathymetry (bottom elevation of river), topography (surface elevation), soil type, landuse types etc. are crucial for improving accuracy of the flood forecasting. Geospatial data area also changing with time due to change of landuse patterns, urbanizations, deforestations, structural interventions on the river, or natural change of the course of the river. It is essential to collect such data geospatial data on a regular interval (yearly) and update the database. At present, the only source of these vital information is collected by the satellite based remotely sensing which suffers from inaccuracy and inconsistency. Often, high resolution data (e.g., LIDAR satellite data) are very expansive. However, many departments of the Govt. of Bangladesh, India and Nepal have purchased high resolution satellite images or conducted survey for a specific region within their countries. Sharing of such geospatial information can be useful and beneficial for disasters like floods, flash floods, river bank erosion, or excessive sediment depositions, land-slides etc. among these countries sharing transboundary river basins.
On the other hand, meteorological data such as rainfall, temperature, sunshine hours, solar radiation, wind, humidity etc. and hydrological data such as water level and discharge in the rivers has been collected on a regular intervals (hourly). These data are essential for prediction ofclimate impacts or forecasting of floods. Hydro-meteorological information is crucial for increasing the accuracy and lead time of the flood forecasting.
During the major floods, forecasting and early warning dissemination plays a greater role to save lives, properties, damage to crops. Accurate flood forecasting and early warning dissemination is one of the major components of flood risk management. It is also mentioned under the Sustainable Development Goal-6 (SDG) that floods and other water-related disasters are responsible for the 70 per cent deaths related to natural disasters. Hence, reducing the risks of flood related disasters by improving accuracy and lead-time of flood forecasting and early warning systems are essential for the country to achieve the SDGs.
Unfortunately, flood related data and information of the transboundary rivers particularly for the Ganges, Brahmaputra, Meghna, Teesta, Dharala, Dudhkumar, Khoai, Kangsha, Jadukatha rivers are either unavailable or in a very limited scale. Daily or twice a daily water level information for a few stations are available for the Ganges, Brahmaputra, Meghna and Teesta river which often found inadequate. Collaboration of flood related information sharing among the courtiers of these transboundary rivers can reduce the risks of flood disasters. Billions of dollars can be saved by providing accurate and well ahead flood information for a country like Bangladesh as its economy primarily depends on agriculture. Basin-wise flood information sharing and flood management can help these countries for their sustainable growth. Many good examples can be found where information of floods is shared among the countries of the transboundary river. The Mekong River Commission (MRC), an inter-governmental agency established by Cambodia, Lao PDR, Thailand and Vietnam, has adopted integrated water resources management (IWRM) in its water strategy plan to properly manage the transboundary waters of the Mekong River. MRC data sharing procedures were institutionalized and have been officially implemented by the four member countries since 2001.
Last year, all the 5 countries of the transboundary rivers shared with Bangladesh have experienced huge floods. In some cases, 2016 floods exceed the record high water levels in some stations. At the Bahadurabad station on the Brahmaputra river, the highest water level was 20.71m which has exceeded the historic record of 20.62m occurred during the 1988 floods. Sharing flood related information among the countries sharing transboundary rivers will not only improve risks of flood disasters but also provides further opportunity to work together to meet the challenges of water sharing. Basin wise collaboration of information sharing during the floods may open the window to work together for better management of water during the dry seasons when water scarcity occurs.
Many studies around the globe reveals that climate change will attribute change of the intensity and duration of the natural disasters such as floods. A recent study of BUET showed that peak floods of Brahmaputra river with a 100-year return period will increase about 10 per cent by the end of the century due to climate change. As countries like Bangladesh, Nepal, India, Bhutan, China suffer from devastating floods in a regular interval, we all need to think about more collaboration and cooperation on geospatial, hydrological and meteorological information sharing among us. Transboundary data sharing is widely recognized as an essential element in the successful reduction of water-related disasters like floods which is a means towards integrating water and natural resources management. Moreover, to achieve the SDGs by 2030, it is time to build the fruitful collaboration on data and information sharing among the countries sharing the transboundary river basins. Policy makers, planners, water managers and major stakeholders should realize that sharing data and information during the natural disasters will benefits everyone of these huge river basins. It might provide opportunity for ensuring food security, energy security, environmental sustainability, sound ecosystems, transboundary navigations and combating climate change related threats!
The writer is a Professor of the Institute of Water and Flood Management at the Bangladesh University of Engineering and Technology, Bangladesh. Email:akmsaifulislam@iwfm.
buet.ac.bd.
|
Editor : M. Shamsur Rahman
Published by the Editor on behalf of Independent Publications Limited at Media Printers, 446/H, Tejgaon I/A, Dhaka-1215.
Editorial, News & Commercial Offices : Beximco Media Complex, 149-150 Tejgaon I/A, Dhaka-1208, Bangladesh. GPO Box No. 934, Dhaka-1000.
Editor : M. Shamsur Rahman
Published by the Editor on behalf of Independent Publications Limited at Media Printers, 446/H, Tejgaon I/A, Dhaka-1215.
Editorial, News & Commercial Offices : Beximco Media Complex, 149-150 Tejgaon I/A, Dhaka-1208, Bangladesh. GPO Box No. 934, Dhaka-1000.
![]() |