Sedimentation and Shifting of Lower Mundeswari and Rupnarayan River, West Bengal, India

The two important embranchmentsEmbranchment of the River of Damodar and Dwarkeswar are MundeswariMundeswari and Rupnarayan,Rupnarayan respectively, which have joined with each other at Marokhana panchyet, Hooghly district, West Bengal, India. In this study area, Hooghly (Pansuli village), Howrah (Kaijuri village), and Midnapur (Vatora village), these three districts are separately located at conjunction point of lower RupnarayanRupnarayan (main channel) and lower MundeswariMundeswari. It’s a fact that, due to continuous sedimentationSedimentation, the lower part of those rivers has deterioratedDeteriorated heavily. So, various soil samples have been collected from riverside surroundings and analyzed sediment sizes by sieving techniques to explain the causes, mechanism, dynamicity, and present situation of sedimentationSedimentation. This area is located in the MonsoonMonsoon region. So, during the rainy season, the water flow or stream power becomes very high due to heavy rainfall, but during the summer or late monsoonMonsoon season, it is comparatively low due to a lack of sufficient rain, which is the main cause of massive sedimentationSedimentation. In comparison to the MundeswariMundeswari River, the River RupnarayanRupnarayan has a higher energy flow of water, depth, stream power, dischargeDischarge, slope, bank-full index, and so on which are measured by different instruments such as Echo-sounder and Current meter, Dumpy level, and so on. River shifting is another important incident in this area. From very past to present, several secondary data shows a shifting trendShifting trends of these two rivers which is a threat for that area. By methods of sedimentationSedimentation analysis and GISGeographic information systems (GIS) techniques, it has been noticed that the shifting trend of the two rivers is uni-directional. By sedimentationSedimentation analysis and Landsat imagery classification, it is showed that from the year 1979–1999, the rate of shifting is 6.5mt and from the year 1999–2019, the rate of shifting is 4.75 mt. In the rainy season, devastating floodsFlood and bank erosion are very common and dangerous incidents every year. It is so affrighting for local peoples and their resources. So, it is clear that these two rivers are the gift of that place, denunciation also.