https://ir.vidyasagar.ac.in/jspui/handle/123456789/71 Sun, 26 Apr 2026 07:19:13 GMT 2026-04-26T07:19:13Z https://ir.vidyasagar.ac.in/jspui/handle/123456789/6280 Title: Changing geo-environmental settings of Henry’s Island and Patibania Island in South-Western Sundarban Authors: Mukherjee, Debasmrity Abstract: The Sundarban region, located on the northern coast of the Bay of Bengal, is the largest mangrove forested region in the world. Occupying the southern end of the Ganga-Brahmaputra basin, this region has formed due to enormous sediment deposition from this river system. Numerous estuarine rivers and creeks have created a complex network of streams, through which the freshwater of the Ganga-Brahmaputra river system as well as the saline tidal water flow. The mangrove forests in this region are biologically very productive and support high biodiversity. Mangroves in Sundarban are vulnerable to climate change and anthropogenic impact. The south-western part of Sundarban exhibits many striking features, including the interplay of estuarine hydrological processes of the tide dominated Hooghly river, and coastal wave and tidal action through many creeks. The resulting diverse geomorphic setup and dense human settlements coexist alongside extensive mangrove forests. Because of these features, this region is ideal for a careful study of the changing geo-environmental settings of the mangrove habitats in Sundarban, including changes in geomorphic, the hydrological and climate attributes. The mangrove ecosystem is coping with the changing environment. For this study, two islands from this region are selected — the Henry’s island and the Patibania island, which themselves exhibit remarkable variation in characteristics, thus convincingly representing the larger southwestern Sundarban region. The physiographic and biogeographic characteristics of these two islands as well as the anthropogenic impacts on them are investigated using data collected from direct field surveys and acquired climate, satellite and tide related information. It is observed that the islands exhibit a diverse set of topographic features, mirroring the larger south-western Sundarban. The soil and ecological characteristics of this region also vary with changing geomorphic features. Tidal drainage loss due to siltation in the inner parts of the islands reduces water inflow, which makes the environment suitable for the development of saltpans and unfavorable for the growth of mangroves. The coastal edges of the islands are facing erosion due to tidal action. The analysis of the climate data for the last two decades indicates a rising trend of temperature and a decreasing trend of rainfall. Analyzing the relationship between the mangrove vegetation cover and climate, it is also perceived that the density of mangrove vegetation decreases with increasing temperature and decreasing rainfall. These two findings together point towards the vulnerability of the mangrove ecosystem in face of climate change. It is found that the decrease in water influx due to tidal drainage loss and declining rainfall has led to an increase of salinity and resulting proliferation of saltpans. Very high salinity levels make the saltpans almost barren and devoid of vegetation. Also, a significant portion of the previous mangrove habitats are now occupied by economic activities, which include aquacultural and tourism related facilities. On the other hand, it is found that the amount of groundwater extracted for human requirements is considerably larger than the replenishment of the groundwater table by monsoonal rainwater. This has resulted in an unsustainable situation. The analyses point to further degradation of the mangrove ecosystem and its environment, if no action is taken to prevent the climatic and anthropogenic adversities. However, it is also observed that artificial canals have a positive impact on the mangrove ecosystem in the inner portions of the islands. Taking all of the above findings into consideration, recommendations are given for the sustainable development involving the mangrove habitat and the inhabitants of this area. This would ensure preservation of the existing mangrove habitats and restoration of the degraded mangroves as well as the continued livelihood of the local communities, which depends on the mangrove ecosystem services. Thu, 07 Oct 2021 00:00:00 GMT https://ir.vidyasagar.ac.in/jspui/handle/123456789/6280 2021-10-07T00:00:00Z https://ir.vidyasagar.ac.in/jspui/handle/123456789/6279 Title: Channel Planform Dynamics in the Himalayan Piedmont Zone - A study on the Chel River Authors: Lama, Sonam Abstract: The present research has attempted to analyze channel planform dynamics of the Chel River during last 62 years in the piedmont of Eastern Sub-Himalayan North Bengal. Channel dynamics is an inherent characteristic of rivers flowing in Terai and Dooars of Sub-Himalayan North Bengal plains and also beyond it southwards in the entire Barind tract of Ganga-Brahmaputra-Meghna system of Bengal basin. In fact, Chel basin falls under the Teesta Basin which is a part of Brahmaputra basin and thus forms a part of the upper Barind tract, an alluvial tract wherein river have been much dynamic and documented records of the same is available for about 250 years since the first maps of the region prepared by Rennell was published in 1780. Channel dynamics studies in India have been mostly concentrated on the large alluvial rivers of Ganga and Brahmaputra. Huge volume of literature is available for upper and middle Ganga plain followed by similarly of upper and middle course of Brahmaputra. In Bengal the study till day is much focused on Lower Ganga plain. Studies on rivers of Terai and Dooars as such are very less and fragmentary too. Unlike rivers of south Bengal the rivers of north Bengal flow through transitional physiography between Himalayas and lower alluvial plains. Thus, though smaller in size and volume of water, they display great dynamics. Within the Terai and Dooars iteself, we find disparity in the amount of studies among the rivers as much study has been done on rivers like Mahananda, Balason, Teesta, Lish, Gish, Jaldhaka, Torsa whereas comparatively studies on Chel River is less and fragmentary. During extensive literature review, the author came across few published research articles on Chel River but couldn’t get any M.Phil and Ph.D dissertation on Chel River basin. The selection of the Chel river for the present study was also prompted by the fact that the Chel river drains through the tectonically active Himalayan region and its foreland, thus gives an opportunity to test response of drainage lines and watershed to the neotectonics. Further, the entire course of the Chel is accessible to verify the results generated by remote sensing and GIS. Field surveys were conducted to measure the channel cross profiles and hydrological parameters at 2km interval. Estimation of surface flow out and sediment out has been achieved through GIS based SWAT model. All morphometric analysis was done using toposheets and SRTM DEM in ArcGIS 10.1. Multi-temporal Landsat images and ASTER DEM were used extensively for reconstruction of historical change in channel morphology and planform. Present study generates huge geomorphologic database and thus will help in giving important inputs necessary for formulating plans and in decision making relating to the basin and the region. Thus, the present work attempts to understand channel dynamics of a small river with 58 km length and 321 km of total watershed area of a data scarce region and basin in particular. Wed, 06 Oct 2021 00:00:00 GMT https://ir.vidyasagar.ac.in/jspui/handle/123456789/6279 2021-10-06T00:00:00Z https://ir.vidyasagar.ac.in/jspui/handle/123456789/6256 Title: Assessment of Beach Stage and Dune Stage Dynamisms for Sustainable Management of Coastal Development Projects – A Study at Mardarmani Coast Authors: Bal, Abhinanda Abstract: Beach morphodynamics is the incoherence and synergic co-modification of intertidal seashore surf zone morphology and the hydro-dynamic elements embracing the wind, beach gradient and sediments. However, the instrumentation and dynamism of sand dunes as a sedimentary depositional circumstance likewise act diversely in varieties of land type by process variables. Such ceaseless change of sedimentary accretional condition over time develop the specific land surface upheld by tropical floral structure and community pattern based on available moisture condition & wind regime. The absence of vegetation from this natural built up veneer increases the ardor of surface stability of sand dunes.Human proceedings with contrasting livelihoods and tourism activities enter into the flow as modifying agents. The eventful fate of the tourism sector evolution on the basis of local tourism products relies on variable conduct of temporal and spatial substitution on the sedimentary depositional facet. This buoyancy will deliver and effect over the recreational advancement, if the climate change initiated coastal disarray accelerates steadily in the near future.This study is an attempt to asses the rational behind the peril environmental change, geomorphic capriciousness and livelihood diversity over the back drop of serene Mandarmani coast of West Bengal. The main aim is to categorize sediment transportation budget in accordance with micro-surficial features driven by hydrodynamic parameters.The very importance of the geomorphological consequences is in the juxtaposition of fluvio-tidal and marine processes superimposed upon Holocene marine transgression and shoreline progradation. The rhythmic seasonal shift from dissipative to reflective nature portrays an extensive characterization of the beach-dune complex. Highest tolerable species varieties must be preferred over casuarina for dune stabilization. Integrated Coastal Zone Management is the only option to utilize the opportunistic natives, environment zoning, vulnerability assessing and sustainable tourist management. Sat, 07 Aug 2021 00:00:00 GMT https://ir.vidyasagar.ac.in/jspui/handle/123456789/6256 2021-08-07T00:00:00Z https://ir.vidyasagar.ac.in/jspui/handle/123456789/5748 Title: Coastal urbanization and population pressure with related vulnerabilities and environmental conflicts - A case study at Medinipur littoral tract, West Bengal Authors: Mondal, Dipankar Abstract: The Ph.D thesis entitled “Coastal Urbanization and Population Pressure with Related Vulnerabilities and Environmental Conflicts - A Case Study at Medinipur Littoral Tract, West Bengal” submitted for examination includes the nature and functions of coastal urbanization over the sensitive environment at Digha, Contai and Haldia; the growth patterns of each urban centres on the diversified coastal habitats and landforms; the demographic status of urban population of the present study areas; estimation of associated risks involved within the process of urbanization in the coastal belt; observation of the urbanization-environment conflicts with related vulnerabilities; and the susceptibility of the management practices to sustain the expanding horizons of such coastal urbanizations in these parts of West Bengal coast. The urban centre of Khadalgobra, including Digha is a census town and it has extended along the shoreline of Contai coastal plain as a beach resort. However, Contai and Haldia are expanded as statutory towns under municipality administration and located above the beach ridge plain and estuarine floodplain of Medinipur littoral tract. The built-up areas of the urban units are increased rapidly over time and space in expanses of sensitive habitats (shorelines, sand dunes, wetlands etc.) of the alluvial coast. The rapid expansion of beach tourism along the littoral tract from New Digha to Mandarmani (24 km shoreline) has created a lot of environmental conflicts between tourism infrastructure development and modification of sensitive coastal environment in the region. The female literacy rate has increased in all three urban centres and over 75 % of people are involved in tourism and transportation-related activities in Digha and Contai urban centres of the beach fringed coast and inland dune ridge coast at present. The trend of average annual rainfall over 35 years periods though decreasing in all three urban centres of the coastal belt (Digha 1648 mm, 1982-2017; Haldia 1856 mm, 1982-2017; and Contai 1599 mm, 1973-2017) but intensities of storm rainfall for a short period create coastal floods in the low-lying areas of the coast. However, the average annual temperature for the said periods is increasing significantly. Groundwater depletion, shoreline erosion, dune degradation, saltwater inundations and conversion of natural wetlands are major impacts of the overuse of resources, population pressures and marine forcing factors (sea level rise, advancing sea and repeated cyclone landfalls) in the low-lying coastal belts at present. Dumping of untreated wastes and associated problems, urban drainage conditions during extreme events (tidal waves, storm surges and storm rainfalls), urban air pollution and saltwater encroachment into groundwater aquifers generated complex consequences of such alarming expansion of the coastal urbanization in the present study area. The existing Coastal Regulation Zone (CRZ) rules, the effort of Integrated Coastal Zone Management (ICZM) activities, the participation of rural people in tourism development processes and multiple activities of Digha-Sankarpur Development Authority (DSDA) are not enough to reduce the conflicts between stakeholders and resource sharing activities and to tackle the advancing sea and climate variabilities of the vulnerable coastal environment fringed with northern Bay of Bengal and the seaward extension of Hugli estuary. As the development of urban areas intensified or spread into vulnerable sites of the coastal belt, so the potential impact of hazards increased in Digha, Contai and Haldia at present as depicted in the work. Tue, 09 Feb 2021 00:00:00 GMT https://ir.vidyasagar.ac.in/jspui/handle/123456789/5748 2021-02-09T00:00:00Z