Columbia University collaborators Chadwick and Steckler built a predictive model for coastal subsidence and elevation change. The model was designed to resolve observed variations and disentangle the effects of climate change and human activities. The model is built upon fundamental principles of effective stress, conservation of mass, and Darcy flow as well as constitutive relations for sediment porosity and shallow-subsurface ecology (e.g., tree roots, animal burrows). As input, the model uses stratigraphic data for the recent (Holocene) sedimentary deposits, near-surface soil properties, and sedimentation rate for a designated site. The model generates a time-series of subsidence and surface-elevation change, which can be directly compared to field measurements and projected into the future. The team validated the model region of Polder 32 in coastal Bangladesh, which boasts a dense clustering of field measurements. Results show the model can accurately resolve twenty-first-century subsidence dynamics within +/- 5 mm/yr., including local amplification of subsidence hazards in response to land use and climate change.
A manuscript presenting the model and its publicly available, open-source components is in preparation for publication at a peer-reviewed scientific journal. The outcome of this work will allow for the generation of new, dynamic Digital Elevation Models (DEMs), which can be utilized across the Jameel Observatory CREWSnet efforts to improve predictions of where water will flow during floods and where waterlogging will occur during intense rains.
Learn more about land subsidence