Reason-A Technical Journal (Formerly Reason-A Technical Magazine)

Gautam Kumar Das ¹, Siddhartha Datta ¹

Affiliations
1 Department of Chemical Engineering, Jadavpur University, Kolkata-700 032, IN

Abstract

The vibrant ecosystem of Sunderbans with its lush green mangrove forest, various types of aquatic species including many rare endemic flora and fauna, birds, crocodiles and the famous Royal Bengal Tiger is a unique Biosphere Reserve. Unfortunately such a productive ecosystem is now exposed to threats of extinction. Besides the natural global phenomena, the land degrading anthropogenic activity is one of the prime factors for this ecological decline. In a forest-society interface, unplanned over exploitation of natural resources is very common. In the case of Sunderbans also, as a result of continuously increasing population pressure almost half of the mangrove forest have been cut down to supply fuel wood, land reclamation for settlement and aquaculture and various other purposes. The situation has become precarious as there seems to be a striking imbalance between exploitation and replenishment, thereby making the ecosystem most fragile. Indiscriminate prawn seed collection, refuse and sewerage discharge from urban areas, spillage of toxic pollutants as well as trashes in the tourist spots of Sunderbans are other anthropogenic factors responsible for environmental degradation of the area. Suitable strategies for the conservation and maintenance of optimum ecological condition of this unique biodiversity have to be planned involving local people, Government and other social organizations.

Keywords

Sunderbans, Mangroves, Prawn Seeds, Shell Fish, Fin Fish, Bidyadhari River, Royal Bengal Tiger.

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Gautam Kumar Das ¹

Affiliations
1 Department of Chemical Engineering, Jadavpur University, Calcutta-700 032, IN

Abstract

Sunderbans soil is typically a physiologically dry soil because plants cannot absorb water properly from the soil due to presence of high amount of salt. The coastal tidal forest, Sunderbans has the saline micaceous deltaic alluvium of humid region. Sunderbans has too saline humic and acid sulphate soils of humid tropical region. Acid sulphate soil has highly acidic pH, high EC, presence of humic (organic) horizon, dominance of sulphate and chloride salts. Substrate soils of different geomorphic regions like riverbank, mudflats and natural levees of Sunderbans are poor in aeration and water holding capacity.

Keywords

Saline Soils, Soil Reactions, Soil Characteristics, Acid Sulphate Soils, Micronutrients, Metal Oxides, NPK, Soil Distributions.

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Gautam Kumar Das ¹

Affiliations
1 Department of Chemical Engineering, Jadavpur University, Kolkata-700 032, IN

Abstract

Changes in the local hydrology in the estuarine river waters of Sunderbans are the most important contributory factors attributable to the changing scenario of mangrove ecosystems. Changes in river courses impede fresh water flow towards Sunderbans. All these changes as a result of regional and global processes and climatic changes cause the changes in the salinity, pH, dissolved oxygen, temperature and all other changes in the physico-chemical parameters in the brackish waters of the Sunderbans. Mangrove distribution is limited worldwide depending principally on temperature and salinity variations of the estuarine river waters.

Keywords

Brackish Waters, Temperature Variations, Salinity Declining Trends, Coastal Waters.

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Gautam Kumar Das ¹

Affiliations
1 Department of Chemical Engineering, Jadavpur University, Kolkata–700032, IN

Abstract

Geomorphologically defined areas like mid-channel bars or flood-tidal delta, river mouth bar or ebb-tidal delta, point bar, swash platform, wash-over flat and river banks (levee) have been identified in the Thakuran River of the estuarine Sunderbans. These areas are delineated based on studies of the granulometric properties. A coarsening of graphic mean size (MZ), betterment of sorting (ó1), and negative to positive skewness (SK1) have been noticed from the seaward to landward direction. Variations of these textural parameters are related to decreasing energy levels along the same direction. A bipartite granulometric model of sedimentation having sand-to-mud from the seaward to the landward direction of the tidal creek has been discerned. This is in contrast to a tripartite granulometric model typical of estuaries.

Keywords

Texture, Grain Size, Cumulative Curves, Sorting, Skewness, Kurtosis, Mean Size, Thakuran River, Sunderbans.

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Gautam Kumar Das ¹

Affiliations
1 Department of Chemical Engineering, Jadavpur University, Kolkata– 700 032, IN

Abstract

Thakuran River sediments are typical estuarine. Lithogenic constituents are dominant with about 85-90% in bulk and biogenic components constitute the rest (10-15%). Quartz, feldspars, mica, lithic fragments and some heavy minerals are the main terrigenous constituents. Secondary overgrowth of quartz with multiple rims of inclusions suggests their derivation from sedimentary rocks of different cycles of sedimentation. The heavy mineral assemblage in the sediments lead to conclude that the sediments have been derived from the acid igneous rocks of the Himalayas in the north and the metamorphic rocks of the Precambrian shields of the west and north-west of Bengal Basin. Benthic foraminiferal assemblage indicates a shallow water, moderate to low salinity environment of deposition.

Keywords

Lithogenic Components, Biogenic Components, Heavy Minerals, Acid Igneous Minerals, Metamorphic Sources, Sedimentary Rocks, Thakuran River, Sunderbans.

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Gautam Kumar Das

Abstract

Cyclonic storms happen to be a major event in the coastal peninsular of India emerging from the Bay of Bengal and theArabian Sea in recent times. Cyclones generally devastated Odisha and the Indian and Bangladesh coastal region including Sunderbans, and their adjacent areas along the coastal tract of the Bay of Bengal, but on 3 June 2020, Mumbai along with other districts of Maharashtra faced the lashes of cyclonic storms after a gap of 100 years. As a result of rising sea level due to global warming and climate change, the Indian Meteorological Department, after computation of the yearly occurrences of the storms, states that the numbers of severe cyclones increased by 11 percent in the last decades in the Bay of Bengal and Arabian Sea. Further, the Indian Meteorological Department alerts the inhabitants living in the coastal stretch across the Indian peninsula for frequent occurrences of severe cyclones with 32 percent rise in the last five years duration in the Bay of Bengal andArabian Sea.

Keywords

Climate Change, Cyclonic Hazards, Bulbul, Amphan, Nisarga, Nivar, Burevi, El Niño-La Niña Phenomena.

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Gautam Kumar Das

Abstract

Forest cover mapping exercise for the state ofWest Bengal reflects the districtwise status of forests and its present trends and provides inputs for monitoring of forests and its restoration. District-wise statistics assessed from the biennial reports of the Forest Survey of India reveal the changes in the forest cover for the districts ofWest Bengal from time to time. Specifications of forest related information like forest types, and myths and history are included for all districts. District-wise forest cover change matrix reflects dwindling of the South Bengal's forest cover alarmingly from the eighties of the last century; yet a shift to joint forest conservation by making stakeholders in forestry initiatives and social forestry creation managed by the forest department has yielded the present results. Plantation under the social forestry scheme in almost all the districts of West Bengal has started showing results for the growing stocks. District-wise break-up revealed that South 24 Parganas, Uttar Dinajpur, Murshidabad and Howrah have recorded decrease in forest cover, while Bankura, Paschim Medinipur, Purulia and Birbhum have recorded a rise.There is a net increase of 54.51 sq km in the forest cover from the reported area in India State of Forest Report 2019 in comparison to the data available in the assessment report published by Forest Survey of India in 2017.

Keywords

Bengal Basin, Reclamation,West Bengal, Dense Forest, Moderately Dense Forest, Open Forest,Trees Outside Forest, Mangroves, Dooars, Sunderbans.

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Gautam Kumar Das

Abstract

Jungle Mahal, though vague in its existence either in the representation in the geographical mapping or in the government records, still the term of Jungle Mahal is yet immensely popular for its numerous forest patches, elephant corridor and man-elephant conflict with the local inhabitants. The forest area of the Jungle Mahal (composed of four districts and part of two districts) once is in depleting status, which is now reviving as reported by the Forest Survey of India in 2019. The probable reasons for this increasing scenario of Jungle Mahal are the impact of climate change, change of soil chemical parameters and local people's direct participation with the forest department for forest restoration. As the study of the impact of climate change is continuing, a pilot survey has been taken up to review the physico-chemical parameters of soil in the selected areas from the Jungle Mahal. Results obtained from the soil chemical analysis of the sampled soils up to rooting depth of 30 cm show status quo as recorded before for the forest stands of the south-east part of West Bengal.

Keywords

pH, NPK, Organic Carbon, EC, Acidic soil. Jungle Mahal.

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Gautam Kumar Das

Abstract

A survey has been taken up for statistical analysis on the sampled data collected from the 27 forests of West Bengal for determination of required optimum sample size in the forests including the nature of the vegetation pattern. Sampled data are analyzed in three phases separately applying probability measures of statistical methods. In the first phase, 9 sample spots of 2 forest patches of Garh Jangal and Aduria Forest, then 14 sample spots of the forest patches of 11 districts and overall, 27 sample spots from 19 districts situated all over the state of West Bengal are considered for statistical analysis. From the analysis, higher the survey spots, lower the required optimum sample size is revealed. Results obtained from the statistical analysis for the forest shows likely indications and positive trends that help to understand the vegetation categories, types of dominant timber trees and stem-diameters of the rest forest areas in the state.

Keywords

Optimum sample size, Random sampling. Stem diameter.

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Gautam Kumar Das

Abstract

Coastal zone of West Bengal, characterized as a typical lowland coast under a meso-macrotidal regime, register evidence of accretion and erosion that control configuration of the coastline. At present, West Bengal coast is a hostile coastal tract in nature evidenced by severe erosion that leads to lowering of coastal plains and landward advancement of coastline as it is a cyclone prone area. The coastal zone of the state is the outcome of the combined depositional effects of Ganga-Brahmaputra River and the Bay of Bengal. Tidal fluctuations, wave parameters, longshore currents, sand flats, and beach ridges are the characteristic features of the coastal areas of the state. Major catastrophic events like cyclonic storms, tidal bores, storm surges, breaking types, high tidal range, strong littoral drift that control the coastal configuration of West Bengal are examined accordingly. Nature of beach materials and different sedimentary structures on the intertidal zones are identified. 

Keywords

Coastal divisions, Coastal sectors, Coastal processes, Wave parameters, Coastal waters, Beach characters, Bedforms, Sediment texture, Breaker types

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Gautam Kumar Das ¹

Affiliations
1 19, Raj Krishna Pal Lane, Kolkata - 700 075, IN

Abstract

The river waters of Jalangi got polluted at its downstream stretch at Krishnanagar due to municipal waste discharge as well as mixing of industrial effluent from The Kishan Cooperative Milk Producer Union Ltd even 7-8 years back. Jalangi River water is currently useable for outdoor bathing after drastic sewage treatment by chlorination for disinfection of faecal coliform bacteria as well as using screen and sedimentation tank for the precipitation of different solids remained in the domestic sewage at the outlets of eight drains of Krishnanagar municipality.The water quality rating applying the formula of water quality index shows 60% good and 40% fair conditions of surface water of Jalangi River for the months from January to May 2020 which was almost poor during 2013-14 and 2014-15 respectively. Application of modified standard values for individual parameters for the computation of WQI reveals similarities of WQI values with the data of physicochemical parameters of river waters of Jalangi.

Keywords

Water Quality Index, Water quality rating, Physicochemical parameters, Jalangi River, Churni, Anjana, Mathabhanga

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