Laying of geomattresses for bed protection in the river Hugli—A case study

Abstract

The ports of Calcutta and Haldia in West Bengal, India, are located on the banks of the river Hugli, the name by which the holy river Ganges is known in its lower reaches. The stretch of the river from its confluence with the Bay of Bengal to the ports has been posing persistent problems due to its depleting draft. The sediment transportation characteristics, especially in the estuarine reaches, and the frequent geomorphological changes which the river is prone to undergo are hard to predict due to various varying parameters. With a view to improving the draft in the river, Calcutta Port Trust, apart from measures for dredging, has undertaken construction of a 2800 m long massive guide wall right on the river springing from the northern tip of the Nayachara island after detailed model studies. The hammer head of the guide wall has at its base geomattresses laid for the first time in India as a bed-protective device in a massive scale with indigenous technology. The author who is in charge of this prestigious project narrates the methodology of laying the geomattresses under extremely trying circumstances. The methodology adopted is a wise compromise of the labour-intensive means suitable for developing countries and machine-orientated techniques usually adopted in developed countries.