G43A-1026
Monitoring Coastal Embankment Subsidence and Relative Sea Level Rise in Coastal Bangladesh Using Satellite Geodetic Data
Abstract:
The Bangladesh Delta is located at the confluence of the mega Ganges, Brahmaputra and Meghan Rivers in the Bay of Bengal. It is home to over 160 million people and is oneof the most densely populated countries in the world. It is prone to seasonal transboundary monsoonal flooding, potentially aggravated by more frequent and intensified cyclones
resulting from anthropogenic climate change. Sea level rise, along with tectonic, sediment compaction/load and groundwater extraction induced land uplift/subsidence, have
significantly exacerbated these risks and Bangladesh’s coastal vulnerability. Bangladesh has built 123 coastal embankments or polders since the 1960’s, to protect the coastal
regions from cyclone/tidal flooding and to reduce salinity incursions. Since then, many coastal polders have suffered severe erosion and anthropogenic damage, and require repairs
or rebuilding. However, the physical and anthropogenic processes governing the historic relative sea level rise and its future projection towards its quantification remain poorly
understood or known, and at present not accurate enough or with an adequately fine local spatial scale for practical mitigation of coastal vulnerability or coastal resilience studies.
This study reports on our work in progress to use satellite geodetic and remote sensing observations, including satellite radar altimetry/backscatter measurements over land and in
coastal oceans, optical/infrared imageries, and SAR backscatter/InSAR data, to study the feasibility of coastal embankment/polder erosion monitoring, quantify seasonal polder water
intrusions, observing polder subsidence, and finally, towards the goal of improving the relative sea level rise hazards assessment at the local scale in coastal Bangladesh.