Flood Mitigation in and Around Sangli, Maharashtra, India, by Modification of River Meander Geometry

The Krishna River basin in Western Maharashtra, India, has been facing acute flood problems since 2005. The Krishna River, which originates at Mahabaleshwar in Maharashtra, has a steeper gradient in the initial reach. When the river enters a flatter region after Karad in the Satara District, it travels in a zigzag pattern with many bends and turns with 17 meanders on it. With these meanders with flatter gradients, the river becomes saucer-shaped, which in turn increases flooding and inundation. Straightening and removing the meanders at some places may reduce the channel length and improve the bed gradient, increasing the discharge carrying capacity, which in turn will help to reduce the flood inundation. In this paper, a hydrodynamic analysis with HEC RAS is done with natural river conditions and by removing a meander on the Krishna River, which is just upstream of its confluence with a tributary called Panchganga. The study reveals that removing this meander helps in flood mitigation. The flood level reduction is 1.29 m at Miraj and 0.45 m at Sangli which are the two majorly affected cities along the banks of the Krishna River in the state of Maharashtra.