DSpace Collection:http://inet.vidyasagar.ac.in:8080/jspui/handle/123456789/10752024-03-19T04:40:30Z2024-03-19T04:40:30ZChanging geo-environmental settings of Henry’s Island and Patibania Island in South-Western SundarbanMukherjee, Debasmrityhttp://inet.vidyasagar.ac.in:8080/jspui/handle/123456789/62802021-11-01T10:52:48Z2021-10-07T00:00:00ZTitle: 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.2021-10-07T00:00:00ZChannel Planform Dynamics in the Himalayan Piedmont Zone - A study on the Chel RiverLama, Sonamhttp://inet.vidyasagar.ac.in:8080/jspui/handle/123456789/62792021-11-01T10:22:57Z2021-10-06T00:00:00ZTitle: 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.2021-10-06T00:00:00ZAssessment of Beach Stage and Dune Stage Dynamisms for Sustainable Management of Coastal Development Projects – A Study at Mardarmani CoastBal, Abhinandahttp://inet.vidyasagar.ac.in:8080/jspui/handle/123456789/62562021-11-01T10:10:43Z2021-08-07T00:00:00ZTitle: 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.2021-08-07T00:00:00ZCoastal urbanization and population pressure with related vulnerabilities and environmental conflicts - A case study at Medinipur littoral tract, West BengalMondal, Dipankarhttp://inet.vidyasagar.ac.in:8080/jspui/handle/123456789/57482021-02-11T05:47:09Z2021-02-09T00:00:00ZTitle: 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.2021-02-09T00:00:00Z