Hydro-Geomorphic Analysis of a Meandering Bend of the Ichhamati River at Hugle-Mathpara Region in North 24 Parganas District, West Bengal

The Ichhamati River is well known for its transboundary flow through India and Bangladesh. A major part of the river traverses through North 24 Parganas District in West Bengal, which mostly comes under the tidal regime. In course of time, the non-tidal course of the Ichhamati has degenerated. However, the lower course of the river remains active throughout the year due to tidal activity. In the middle reach, tidal influence reduces significantly toward upstream along with the presence of a number of angular meandering bends. The study area, located in Baduria and Swarupnagar blocks of North 24 Parganas, is characterised by a meandering bend of Ichhamati that has changed both spatially and temporally. To show the morphological changes in this area, SoI topographical maps and satellite images have been used, complemented by field surveys. Water samples were collected to find out the variation in sediment concentration during flood and ebb tide. It is found that the alignment of the Ichhamati meander at Hugle-Mathpara area has changed from curved to angular pattern in the last 100 years. The altered meander configuration can be related with tidal movement in the river. During the same period, the channel width has decreased 2.2 times due to sedimentation. Due to this, the present channel is unable to contain discharge within its banks during high tides. The channel discharge varies significantly during a tidal cycle. There is noticeable tidal asymmetry in the flood-dominant Ichhamati channel that causes deposition of sediment load on the riverbed. Consequently, the natural flow of the river is hindered which may lead to further degeneration of the river in near future