Bengal Delta Research Articles

Towards an efficient storm surge and inundation forecasting system over the Bengal delta: chasing the Supercyclone Amphan

Abstract. The Bay of Bengal is a well-known breeding ground to some of the deadliest cyclones in history. Despite recent advancements, the complex morphology and hydrodynamics of this large delta and the associated modelling complexity impede accurate storm surge forecasting in this highly vulnerable region. Here we present a proof of concept of a physically consistent and computationally efficient storm surge forecasting system tractable in real time with limited resources. With a state-of-the-art wave-coupled hydrodynamic numerical modelling system, we forecast the recent Supercyclone Amphan in real time. From the available observations, we assessed the quality of our modelling framework. We affirmed the evidence of the key ingredients needed for an efficient, real-time surge and inundation forecast along this active and complex coastal region. This article shows the proof of the maturity of our framework for operational implementation, which can particularly improve the quality of localized forecast for effective decision-making over the Bengal delta shorelines as well as over other similar cyclone-prone regions.

Rural out‐migration as a coping strategy in the drought‐prone areas of Rarh region of Eastern India

AbstractThe present study in the Rarh region (a region between Chota Nagpur Plateau and the Ganges Delta) of West Bengal analyses the impact of drought on the rural households in the eastern India villages and investigates the importance of temporary migration as a coping strategy in times of drought. As many as 82 of a total of 190 households were randomly selected for collection of data with the help of a structured household schedule. The study found that the propensity of male out‐migration increased due to regular droughts in the region. Severe drought conditions coupled with crop failure made most marginal and small landholding households vulnerable to food insecurity due to poor adaptive capacity and resilience. The majority of the landholding farmers under such conditions resort to seasonal out‐migration to sustain themselves. Temporary migration is a coping strategy for the survival of rural households during the drought periods.

Border Environments: An Introduction to the Special Issue

“Border Environments” is deeply informed by this rich body of recent studies, which has not only exposed the overlaps between geopolitics, biopolitics, and ecopolitics of migration but also laid open the concept of borders themselves as sites in which political economy and political ecology collide, intersect, and shape each other. Over the course of a global pandemic that simultaneously upended all notions of border control and continues to have a devastatingly disproportionate effect on migrant populations and border communities not just in the Americas but across the world, “Border Environments” coalesced into a multidisciplinary, multilocational, and multidimensional investigation of the space, place, and concept that was conspicuously and persistently absent from the macrostructural analyses of climate change and migration. Each contributor engages in rich, site-specific explorations of such interfaces, the scope of their work extends far beyond the southern border of the United States. Iconologies, narratives, aesthetic forms and performative practices examined in this issue put the heterogenous landscapes of Latin America in generative dialogue with other distant and proximate, intra- and inter-national border environments: the Marcellus Shale that connects New York and Pennsylvania, the Gangetic delta straddling India and Bangladesh, the sandy straits of the South China Sea.

Gastropolitics: Speaking in Tongues

Gastropolitics: Speaking in Tongues

Arsenic in the geo-environment: A review of sources, geochemical processes, toxicity and removal technologies

Impact of arsenic (As) contaminated groundwater on human health, through drinking and irrigation practices, is of grave-concern worldwide. This paper present the review of various sources, processes, health effects and treatment technologies available for the removal of As from arsenic contaminated water. Groundwater with high As concentration is detrimental to human health and incidents of As contamination in groundwater had been reported from different parts of the globe. More serious known As contamination problem as well as largest population at risk are found in Bangladesh, followed by West Bengal state in India along the Indo-Gangetic plains. Large scale natural As contamination of groundwater is found in two types of environment such as strongly reducing alluvial aquifers (ex. Bangladesh, India, China and Hungary) and inland basins in arid or semi-arid areas (ex. Argentina and Mexico). The provisional guideline of 10 ppb (0.0 l mg/l) has been adopted as the drinking water standard by World Health Organization (WHO). In the aquatic environment, the release, distribution and remobilization of As depend on temperature, redox potential, speciation, and interaction between liquid solution and solid phases. As predicaments in the environment is due to its mobilization under natural geogenic conditions as well as anthropogenic activities. Arsenic mineral is not present in As contaminated alluvial aquifer but As occurs adsorbed on hydrated ferric oxide (HFO) generally coat clastic grains derived from Himalayan mountains. As is released to the groundwater mainly by bio-remediated reductive dissolution of HFO with corresponding oxidation of organic matter. The development of strongly reductive dissolution of mineral oxides (Fe and Mn) at near-neutral pH may lead to desorption and ultimately release of As into the groundwater. As release through geochemical process is more important factor in alluvial aquifers causing As contamination rather than sources of arsenic. As is a toxin that dissolves in the bloodstream, rendering the victim susceptible to disease of the skin, bones, and also cancer of liver, kidney, gall bladder and the intestines. It is necessary to adopt highly successful technology to treat As contaminated water into the acceptable limit for human consumption. Universally accepted solutions are not developed/available even after the lapse of almost forty years since slow As poisoning identification in tens of millions of people especially in Bengal delta. The issue poses scientific, technical, health and societal problems even today.

Variation of salinity in the Sundarbans Estuarine System during the Equinoctial Spring tidal phase of March 2011

The Sundarbans Estuarine System (SES), comprising the southernmost part of the Indian portion of the Ganga-Brahmaputra delta bordering the Bay of Bengal, is India’s largest monsoonal, macro-tidal, delta-front estuarine system. The Sundarbans Estuarine Programme (SEP), covering six semi-diurnal tidal cycles during 18–21 March 2011 (the Equinoctial Spring Phase), was the first comprehensive observational programme in the SES. The 30 observation stations, spread over more than 3600 $$\hbox {km}^2$$ , covered the seven inner estuaries of the SES: the Saptamukhi, Thakuran, Matla, Bidya, Gomdi, Harinbhanga, and Raimangal. At all stations or time-series locations (TSLs), the water level was measured every 15 min and water samples were collected every hour for estimating salinity. We report the observed spatio-temporal variations of salinity in this paper. The mean salinity over the six tidal cycles decreased upstream and the mean range of salinity over a tidal cycle increased upstream. In addition to this along-channel variation, the mean salinity also varied zonally across the SES. Salinity was lowest in the eastern SES, with the lowest value occurring at the TSLs on the Raimangal. Though higher than at the Raimangal TSLs, the mean salinity was also low at Mahendranagar, the westernmost TSL located on the West Gulley of the Saptamukhi. Salinity tended to be higher in the central part of the SES. CTD (conductivity–temperature–depth) measurements at three stations on the Matla show a well-mixed profile. Only the Raimangal has a freshwater source at its head. Therefore, the upstream decrease of salinity in the SES is likely to be the effect of the preceding summer monsoon, which would have freshened the estuary, and the ingress of salt from the seaward end due to the tide following the cessation of of the monsoon rains. The freshwater inflow from the Raimangal leads to the lowest salinities occurring in the eastern SES. The lower salinity in the western SES also suggests inflow from the Hoogly estuary, whose freshwater source is regulated via the Farakka Barrage. At 20 of the 30 TSLs, the salinity varied semi-diurnally, like the water level, and the maximum (minimum) salinity tended to occur at or around high (low) water. The temporal variation was more complex at the other 10 TSLs. Even at the TSLs at which a tidal stand exceeding 75 min was seen in the water level, the salinity oscillated with a semi-diurnal period. Thus, the salinity variation was unaffected by the stand of the tide that has been reported from the SES.

Are farmers willing to pay for participatory climate information services? Insights from a case study in peri-urban Khulna, Bangladesh

Among technological adaptation options, climate information services (CIS) offers high potential as a means to offset climate change impacts and build resilience in farming areas of developing countries. This study explores the potential of CIS, by investigating the case of participatory CIS development in the Lower Ganges Delta of Bangladesh. Specifically, we examined the value farmers attached to a co-developed CIS as decision support tool and the price farmers were willing to pay for CIS subscriptions. Based on a hypothetical market for CIS, we used contingent valuation with a double-bounded dichotomous choice format to determine farmers willingness to pay (WTP) for CIS. Two samples were included: an experiment group of farmers exposed to and trained in CIS use for farm decision-making and a control group of farmers without prior exposure to CIS. More than 90% of farmers in the experiment group expressed willingness to pay for CIS, compared to 75% of the control group. The annual subscription fees farmers were willing to pay ranged from 970.92 taka (US $11.45) to 1387.20 taka ($16.36). WTP was greater among farmers who had participated in CIS co-development. The main factors influencing farmers’ willingness to pay were CIS cost and prior exposure and training to CIS. Given that Bangladesh has more than 16.5 million farm households, these findings suggest huge market potential for CIS. Based on the high potential of participatory CIS, governmental institutions, the private sector and social entrepreneurs are called upon to develop CIS for smallholders, to unlock smallholders’ agriculture potential.

Groundwater arsenic contamination in the Bengal Delta Plain is an important public health issue

There is a close association between human biology, epidemiology and public health. Exposure to toxic elements is one area of such associations and global concerns. The Bengal Delta Plain (BDP) is a region where contamination of ground water by arsenic has assumed epidemic proportions. Apart from dermatological manifestations, chronic exposure to arsenic causes a heavy toll through several carcinogenic and non-carcinogenic disorders. This article provides a global overview of groundwater arsenic contamination in the BDP region, especially the sources, speciation, and mobility of arsenic, and critically reviews the effects of arsenic on human health. The present review also provides a summary of comprehensive knowledge on various measures required for mitigation and social consequences of the problem of arsenic contaminated groundwater in the BDP region.

Modeling and Management Option Analysis for Saline Groundwater Drainage in a Deltaic Island

Understanding the interactions between shallow saline groundwater and surface water is crucial for managing water logging in deltaic islands. Water logging conditions result in the accumulation of salt in the root zone of crops and detrimentally affect agriculture in the economically and socially backward deltaic region of West Bengal and Bangladesh. In this paper, we undertook a modeling study of surface water–groundwater interactions in the Gosaba Island of Sundarbans region of the Ganges delta using MODFLOW followed by comprehensive parameter sensitivity analysis. Further, scenario analyses (i.e., no-drain, single drain, three drains) were undertaken to evaluate the effectiveness of drainage infrastructure to reduce saline water logging conditions. The evaluation indicated that installation of three drains can remove water at a rate of up to −123.3 m3day−1 and lower the water table up to 0.4 m. The single drain management scenario could divert water at the rate of −77.9 m3day−1 during post monsoon season, lowering the shallow saline groundwater table up to 0.1 m. This preliminary modeling study shows encouraging results to consider drainage management as to solve the increasing challenge of water logging and salinity management in the deltaic region. The insights will be useful for farmers and policymakers in the region for planning various sustainable saline groundwater management. Building drainage infrastructure could potentially be part of initiatives like the national employment guarantee scheme in India. In the future, this model can be coupled with solute transport models for understanding the current status and future expansion of salinity in the study area. Further modeling and optimization analysis can help identify the optimal depth and spacing of drains.

Impact of flood inundation and water management on water and salt balance of the polders and islands in the Ganges delta

Inundation by sea water in coastal areas can devastate cropping; recovery from the impacts can be slow. We used a water and salt balance model of polders to investigate the impacts of and recovery from flood inundation by sea water. We applied the model to three polders in the Ganges delta: Amtali, with high rainfall and low salinity; Dacope with intermediate rainfall and salinity; and Gosaba, with lower rainfall and higher salinity. Dacope and Gosaba were inundated a few years prior to our study, and the model calibration is pertinent to the recovery period. The calculated evapotranspiration from the polder (indicating crop growth) was dramatically reduced following inundation, and the calculated salt concentration in the soil water and shallow groundwater greatly increased. The model simulations showed that recovery depends on several factors, in particular how well the soil in the polder is drained and therefore how well salt is flushed out. Our simulations suggest that with sound maintenance of infrastructure and sound management, particularly of soil drainage, the polders and islands of the Ganges delta could recover fairly quickly from inundation events.

Identification of Paleochannels Using Remote Sensing: a Study on Upper Gangetic Delta in Parts of Murshidabad and Nadia Districts, West Bengal

Identification of Paleochannels Using Remote Sensing: a Study on Upper Gangetic Delta in Parts of Murshidabad and Nadia Districts, West Bengal

Groundwater suitability for irrigated agriculture in Alluvial Bengal delta plain: Areview

<p>Groundwater is a vital source of irrigation and domestic purposes in Bangladesh, and hence, it must satisfy the water quality guidelines. The study has selected eleven (11) Districts of Bangladesh and collect secondary data regarding the irrigation water quality of groundwater. Several irrigation water indices, such as soluble sodium percentage (SSP), sodium adsorption ratio (SAR), magnesium adsorption ratio (MAR), residual sodium carbonate (RSC), Kelly’s ratio (KR), permeability index (PI), and irrigation water quality (IWQ) index are applied to evaluate irrigation water quality. According to IWQindex, the results showed 25.5% of water samples fell in highly suitability water type, whereas 33.5% exhibited low suitability type, and the remaining 41% were showed medium suitability for irrigation purposes. The values of SAR, SSP, RSBC, and MAR indices showed that about 31-64% of water samples were very good, whereas 5-20% were very poor for the same purpose. The results of TDS, EC, and total hardness showed good results as 88-93% of water samples fell in fair to excellent quality. The salinity hazard was found in the groundwater of coastal areas and completely unfit for irrigation. The study findings would help for improving the management of the groundwater resources for agricultural purposes in Bangladesh.</p>

Old Routes, New Dreams: Reminiscences of the Southern Silk Road and Bengal-China Connectivities

Abstract An increasing optimism at the prospect of “shared prosperity” has revived attention on ancient historical routes such as the Southern Silk Road compelling us to rethink notions of the “centre” and the “periphery” in comprehending binaries of nation-states and agencies of globalization. This article focuses on revisiting circulatory movements and networks from the past across land and sea between Bengal delta and China in strengthening the networks and a new alignment of communities and economic possibilities. It explores some of the lesser-studied historical routes in the region and different dimensions of “place making” in the popular imagination and new synergies to redefine the Bengal-China connections.

Opportunities and risks with early sowing of sunflower in a salt-affected coastal region of the Ganges Delta

On low-lying land in the Ganges Delta, waterlogging, salinity, and poor soil structure are constraints to intensifying cropping systems. Early sowing of dry season (rabi) crops in this area is hypothesized to increase yield potential because the current late sowing exposes the crop to less favourable temperature conditions, soil dryness, and salinity stresses. Field experiments were conducted over 2 years to identify the opportunities and challenges of early sowing between mid-November and mid-December for maximizing sunflower yield in Southern Bangladesh. Sunflower was dibbled into untilled wet soil on five occasions (23 and 30 November and 10, 20, and 30 December in 2016–2017 and 25 November, 14 and 25 December, and 10 and 25 January in 2017–2018), with two mulching treatments (rice straw at ~ 5 t ha−1 and 15–20% rice residue retention). Sowing before 15 December was associated with larger heads, more seeds per head, greater seed weight, and higher grain yield (3.5–4 t ha−1) in the first year, but early sowing was also risky since, in the second year, the sunflower sown on 25 November was hampered by heavy rainfall, which depressed yield compared to crops sown on 15 December. Increased yield from early sowing before 15 December was associated with higher soil water, lower soil salinity, and higher solute potential compared to sowing after 15 December. Lower yield in late sown crops was also associated with increased temperature at grain-filling stage. The rice straw mulch significantly improved soil water availability, reduced soil salinity, increased soil solute potential, and increased yield in the second year. In this paper, we show for the first time that sunflower sown before 15 December in the Ganges Delta has higher yield potential, but to gain the benefits of the earliest sowing, growers will need to manage the increased risk of yield loss due to waterlogging.

Impact of climate change and management strategies on water and salt balance of the polders and islands in the Ganges delta

Enhancing crop production, particularly by growing a crop in the typically-fallow dry season is a key strategy for alleviating poverty in the Ganges delta region. We used a polder water and salt balance model to examine the impact of several crop management, salt management and climate change scenarios on salinity and crop evapotranspiration at Dacope and Amtali in Bangladesh and Gosaba in India. A key (and unsurprising) finding is that salt management is very important, particularly at the two drier sites, Dacope and Gosaba. Good salt management lowers salinity in the shallow groundwater, soil and water storage ponds, and leads to more irrigation. Climate change is projected to alter rainfall, and this in turn leads to modelled increases or decreases in runoff from the polders, and thence affect salt concentrations in the soil and ponds and canals. Thus, the main impacts of climate change are through the indirect impacts on salt concentrations, rather than the direct impacts of the amount of water supplied as rainfall. Management practices to remove salt from polders are therefore likely to be effective in combatting the impacts of projected climate change particularly at Dacope and Gosaba.

Spatiotemporal variations in anthropogenic marine litter pollution along the northeast beaches of India.

Marine litter is widely distributed in marine environments and has been a severe concern worldwide, due to the disposal of waste from diverse sources. The severity of this threat has garnered increasing attention in India over the last decade, but the full consequences of this pollution are yet to be quantified. To estimate the spatiotemporal distribution, composition and beach quality of marine litter pollution, 17 beaches along the Hooghly estuary, a part of the Gangetic delta was studied. Marine litter was collected from 100m long transects during two seasons (monsoon and post-monsoon). The OSPAR monitoring standard was applied to the 16,597 litter items collected, then grouped under 6 types and 44 categories. In terms of number, litter abundance was higher during monsoon (1.10±0.39 items/m2) than that of post-monsoon (0.86±0.32 items/m2). Most of the beaches were categorized as low cleanliness as computed by the general index and clean coast index and the good for the pellet pollution index. Hazardous litter constituted 6.5% of the total collected litter items. The model prediction revealed that the influence of high discharge from Hooghly, Rasulpur and Subarnarekha River carried enormous anthropogenic litter to the northeast beaches. The litter flux decreases with an increase in distance from the shore, and act as a sink to the sea-floor. The results denote that the distribution and typology of marine litter were representatives of household, tourism and fishing, which in turn highlights the need for better regional litter management measures. Suggested management practices include source reduction, mitigation, management of beach environment and change in littering behaviour through environmental education.

PROJECTION OF NEW CANCER CASES IN THE STATE OF WEST BENGAL, INDIA - 2020: Estimated district wise new cancer cases in West Bengal-2020

It is essential to project cancer incidence for planning cancer control actions, health care and allocation of resources in specific region. Till date no projection of cancer cases according to primary sites and district wise distribution of the cancer cases for the state of West Bengal are available in the literature. In West Bengal only one Population Based Cancer Registry (PBCR) for Kolkata is ongoing cancer registration in West Bengal which is based on urban population only but there is no Population Based Cancer Registry (PBCR) for rural West Bengal Kolkata. PBCR is helpful for the projection of cancer cases in any region. Here the cancer burden for the state of West Bengal had been made to understand the magnitude of cancer problem for the calendar year 2020. The age, sex, primary site and district-wise cancer incidences were projected on the basis of data along with populations covered by the PBCRs obtained from the report of National Cancer Registry Programme (NCRP) published by National Centre for Disease Informatics and Research (NCDIR), Indian Council of Medical Research (ICMR) for the period 2005-2014. Thus pooled age-sex specific cancer incidence rates for urban area were obtained by taking weighted averages of 18 PBCRs of India based on exclusively urban population with respective registry populations as weights. Pooled age sex specific cancer incidence rates for rural area were obtained by taking weighted averages of 15 PBCRs of India based on rural, district and state population with respective registry populations as weights. The pooled incidence rates were assumed to represent the incidence rates for the state of West Bengal. Populations of this state according to age and sex exposed to the risk of development of cancer in 2020 were obtained from the report of Registrar General of India providing population projections for the state for 2020. Population forecasts were combined with the pooled incidence rates to estimate the projected number of cancer cases by age, sex and site of cancer for 2020. The projections were carried out for the various leading sites as well as for ‘all sites’ of cancer. The leading site of cancers, namely those of tobacco related cancers, breast and cervical cancers in women account for over 50 to 60 % of all cancers. Adjustments were made for increasing tobacco habits, exposure to arsenic, Gangetic delta region and also adjustments for increasing trends of lung, prostate, mouth, tongue, and larynx in males and that for breast, cervix uteri, ovary, gall bladder and lung in females were made, the estimates may further increase. The main factors contributing to high burden of cancer over the years are increase in the population size as well as increase in proportion of elderly population, urbanization, Gangetic delta and arsenic exposure. This projection of cancer incidence will help the policy planners for strengthening and augmenting the existing diagnostic/treatment facilities. Also it will help the researchers to plan their research activities in the field of cancer. Keywords: Projection - Cancer incidence - Magnitude of cancer –District wise– West Bengal

Tariq Omar Ali. A Local History of Global Capital: Jute and Peasant Life in the Bengal Delta.

T<scp>ariq</scp> O<scp>mar</scp> A<scp>li</scp>. <i>A Local History of Global Capital: Jute and Peasant Life in the Bengal Delta</i>.

Debjani Bhattacharyya. Empire and Ecology in the Bengal Delta: The Making of Calcutta; Sudipta Sen. Ganges: The Many Pasts of an Indian River; Sunil Amrith. Unruly Waters: How Rains, Rivers, Coasts, and Seas Have Shaped Asia’s History

D<scp>ebjani</scp> B<scp>hattacharyya</scp>. <i>Empire and Ecology in the Bengal Delta: The Making of Calcutta</i>; S<scp>udipta</scp> S<scp>en</scp>. <i>Ganges: The Many Pasts of an Indian River</i>; S<scp>unil</scp> A<scp>mrith</scp>. <i>Unruly Waters: How Rains, Rivers, Coasts, and Seas Have Shaped Asia’s History</i>

A River Is Not a Pendulum: Sediments of Science in the World of Tides

AbstractThis essay explores the history of the silty sediments that make up the littorals of the Bengal Delta to see how they emerged as an object of scientific inquiry and as part of a hydrosocial...