GSA Annual Meeting in Phoenix, Arizona, USA - 2019

Paper No. 299-12
Presentation Time: 5:00 PM


KARIM, Mir Fazlul, Geocomp Corporation, Geotesting Express Inc., 125 Nagog Park, Acton, MA 01720, KHANDAKER, Nazrul I., Geology Discipline, Earth and Physical Sciences, York College Of CUNY, 94-20 Guy R. Brewer Blvd, Jamaica, NY 11451, HAQUE, Shahidul, Consultant, Municipal Engineering, 155 Betony Drive, Richmond Hill, Ontario, ON L4R OP3, Canada, RAHMAN, M. Zillur, Department of Geology, University of Dhaka, Bangladesh, Dhaka, 1000, Bangladesh, HASSAN, Muhammad Qumrul, Department of Geology, University of Dhaka, Dhaka, 1000, Bangladesh; Department of Geology, University of Dhaka, Dhaka, 1000, Bangladesh, KAMAL, ASM Maksud, Department of Disaster Science and Management, University of Dhaka, Dhaka, 1000, Bangladesh, AHMED, Masud, New York City Department of Environmental Protection, Geotechnical Section, NYCDEP, 59-17, Junction Blvd, Queens, New York, NY 11373 and SAYEED, Belal A., Dewberry Geotechnical Company, New York, NY 10001

The Naria town of Bangladesh is developed on the right bank of the Padma River. The bank is an old natural levee of Meghna River. The Holocene-Recent geology of Naria is actively dominated by the fluvial processes of Ganges-Brahmaputra-Meghna River system where the deltaic sediments are characterized as unconsolidated fine sand and silt, covered by thin veneer of clayey silt and loam. The annual volume of water discharge and flow dynamics are dependent on the intensity of the rainfall, runoff and the length of dry winter. Excessive river bank erosion, channel avulsion, renewed submergence of floodplains, and formation of natural levees and channel-bars are due to natural geomorphological processes that impact the area by inevitable ground failures. The geological attributes of ground condition and drastic variations in water levels make the area extremely vulnerable to severe bank failures and erosion.

A unique erosion phenomenon prevailing in this part of Bengal delta prompted this study. During Aug-Sept, 2018 a sudden complex attenuation of current, wave and vortex in the Padma water flow caused an extraordinary disaster and made more than 5000 people homeless overnight by devouring away houses including concrete buildings, factories and markets. It is observed that geologically the Padma River remained confined within a width of 5 miles striking NW-SW trend following the margins of older alluvium and Faridpur Trough. The river tends to a meandering pattern consisting of deep vertical trenches along the Naria curvature. The deep trenches form along right bank and render the ground increasingly more vulnerable to subaqueous slope failure due to presence of thick (~200 ft.) alternating cross-bedded silt and micaceous fine sand of very high dilatancy and low angle of friction.

The present study identifies some application of technological advancement for developing real-time engineering geological mapping systems for monitoring and managing complex river bank erosion. Large scale 3D engineering geological map coupled with air-borne photogrammetric and radar inferrometry methods can be applied for real-time monitoring and prediction of differential settlements, subaqueous failures and ground movement. The point cloud maps developed using data from these systems can refine engineering geological maps for decision makers and improve the design of protective measures and sustainable engineering structures.

  • Final GSA 2019 Naria Presentation Mir Fazlul Karim.pdf (8.0 MB)