Teesta Research Articles

Indo-Bangladesh Transboundary Water-Sharing of the Ganges and Teesta Rivers: Through the Lens of International Law and Practice

Though international water law emphasises ensuring equitable and sustainable utilisation of water resources by all riparian states, most often transboundary rivers are used selfishly and unsustainably by upstream countries. Bangladesh and India, two neighbours in South Asia, share 54 rivers and Bangladesh stands as a downstream country for all of them. Amongst all the rivers, the Ganges and the Teesta are the most contested ones and this article has investigated the issues surrounding their sharing and utilisation. More specifically, the article has analysed the contested Farakka Barrage and bilateral arrangements especially the Ganges Water-Sharing Treaty, 1996, and related issues on the touchstone of existing legal architecture and jurisprudence. Also, the existing no-agreement situation of the Teesta River has been analysed in view of international law and practice. The author considers the Ganges Water-Sharing Treaty, 1996 as a milestone in the mutual relationship between India and Bangladesh, but at the same time suggests further improvement in line with international legal norms and practices. As regards the Teesta, the article argues that India’s approach towards the Teesta River reflects a total disregard for the principle of equitable and reasonable utilisation and the principle of no-significant harm.

The Sikkim flood of October 2023: Drivers, causes and impacts of a multihazard cascade.

On 3 October 2023, a multihazard cascade in the Sikkim Himalaya, India, was triggered by 14.7 million m3 of frozen lateral moraine collapsing into South Lhonak Lake, generating an ~20 m tsunami-like impact wave, breaching the moraine, and draining ~50 million m3 of water. The ensuing Glacial Lake Outburst Flood (GLOF) eroded ~270 million m3 of sediment, which overwhelmed infrastructure, including hydropower installations along the Teesta River. The physical scale and human and economic impact of this event prompts urgent reflection on the role of climate change and human activities in exacerbating such disasters. Insights into multihazard evolution are pivotal for informing policy development, enhancing Early Warning Systems (EWS), and spurring paradigm shifts in GLOF risk management strategies in the Himalaya and other mountain environments.

Tectonics and climate controlled sedimentary provenance in the teesta basin since mid-holocene

Erosion of the Himalaya Mountain and subsequent deposition of sediments in the flood plains, and distal fans are primarily regulated by tectonics, climates, lithology, and relief of the region. These eroded sediments preserve their chemical and isotopic compositions in their depositional archive, which can be used to trace the erosion processes, assess the relative role of controlling factors and their spatio-temporal variations. The present study have analysed the 87Sr/86Sr and ԐNd of in silicate phase of sediment recovered from a ~ 40 m long sedimentary core representing ~8 ky of sediment accumulation in the Teesta River mega fan. The lithostratigraphy of the core indicates rapid aggradational nature of the Teesta mega fan. The 87Sr/86Sr and ԐNd display large variability with depth, which ranges from 0.75700 to 0.89294 and − 15.1 to −25.0, respectively. The observed 87Sr/86Sr and ԐNd values in the core sediments have been interpreted in terms of differential sediment contribution from the Higher and the Lesser Himalayan lithology. The 87Sr/86Sr and ԐNd isotope profiles and estimated fractional sediment contributions identify the Lesser Himalaya as the major sediment contributor to the Teesta basin since the mid-Holocene, unlike the other Himalayan River basins, dominated by sediments from the Higher Himalaya after the Last Glacial Maximum. The rapid exhumation and erosion of the tectonically active Rangeet window with the focused precipitation and presence of rock types vulnerable to weathering in the Lesser Himalaya of the basin appear to be the major factors resulting the sedimentary budget of the Teesta River basin over at least last 8 ky. Our assessment suggests that tectonic activity and climate have a competitive effect for the observed sedimentary budget, with an additional role of lithology. The study infers a major control of active tectonics, precipitation, and lithology on the sedimentary budget of the Himalayan River basins.

Application of Entropy-AHP and WASPAS methods for prioritizing the sub watersheds of Teesta River basin in terms of soil erosion susceptibility

Soil erosion, primarily driven by natural and human-induced factors, is a significant contributor to soil degradation and natural disasters. Effective watershed management practices can mitigate these issues. This study aimed to create a soil erosion susceptibility map for the sub-watersheds of the Teesta River using the Weighted Aggregated Sum Product Assessment (WASPAS) model. Ten morphometric parameters were considered to assess susceptibility, including Bifurcation Ratio, Circulatory Ratio, Basin Length, Stream Frequency, Drainage Density, Basin Perimeter, Basin Width, Shape Factor, Drainage Texture, and Elongation Ratio. The relative weights of these parameters were determined using the AHP-ENTROPY method. The integrated weights were then applied in the WASPAS model to rank the sub-watersheds. Results indicate that sub-watersheds Rangit (SW5), Chel (SW14), Rangyong Chhu (SW4), Lhonak Chhu (SW1), Chakung Chhu (SW6), and Lish (SW13) are highly susceptible to soil erosion. These sub-watersheds should be prioritized for conservation efforts. The originality of this study lies in its application of the WASPAS method in the context of soil erosion, providing a more comprehensive and accurate assessment compared to traditional methods.

Prioritization and Regionalisation of Sub-watershed for Flash Flood Susceptibility in the Upper Teesta River Basin, North Sikkim, India

Prioritization and Regionalisation of Sub-watershed for Flash Flood Susceptibility in the Upper Teesta River Basin, North Sikkim, India

Genotoxic impact of agricultural insecticides as contaminants of river Teesta on the resident fish Pethia Conchonius.

Fish, being highly sensitive to changes in the physico-chemical parameters of water, are good indicators of contamination. Teesta, a prominent northern West Bengal River system, is increasingly contaminated due to anthropogenic activities. This study aims to determine agricultural pesticide contamination and its genotoxic impact on the resident fish, Pethia conchonius, as an experimental organism. Sample water analysis from three riverine sites I, II & III, showed the presence of the insecticides imidacloprid (IMI), chlorpyrifos (CPF), bifenethrin (BF), cypermethrin (CP), difenthiuron, acetamiprid (AC) in the sites II and III only with adjoining agricultural lands. Comet assay revealed a significantly lower % Head DNA (~ 1.2 times), higher %Tail DNA (~ 16 times), and %Tail length (~ 3.1 times) in the gills of Pethia conchonius from sites II and III. About 4 and 10 times increase of micronuclei and other nuclear abnormalities were also noted in the erythrocytes of the fish from sites II and III than I, which was not contaminated. The antioxidant enzymes SOD, CAT, and GST activity and MDA levels were significantly higher (p < 0.05) in the liver samples from sites II and III, while AChE activity was significantly decreased (p < 0.001) in the brain tissues. Moreover, the sod, cat, and gpx expression in the hepatic cells were significantly upregulated compared to the β actin mRNA indicating increased oxidative stress. Increased genomic damage, antioxidant enzyme activity, higher MDA levels, decreased AChE activity in the brain, and the upregulation of hepatic genes strongly suggested the genotoxic effects of the detected insecticides in combination with other contaminants.

Hydrological response to climate and land use and land cover change in the Teesta River basin

ABSTRACT The Teesta basin is shared by Bangladesh and India, holds significant importance in the bilateral relationship, and sustains the livelihoods of over 30 million people in Bangladesh. Employing a cellular-automata model (CA), we accurately estimate LULC for the 2020s and projected for the 2050s and 2080s. A semi-distributed hydrological model, Soil Water Assessment Tool (SWAT), is used to generate flow for the base period (1995–2014), the near future (2035–2064), and the far future (2071–2100). SWAT model is forced by eight general circulation models (GCMs) under two socioeconomic pathways (SSP245 and SSP585). The CA-Markov prediction indicates LULC changes, especially increased agriculture and settlements by 76 and 42%, and decreased forest and water by 13 and 36%, respectively, which are expected by 2050s and will influence discharge patterns. This results in additional discharge increases of 4% (–8 to 5%) for SSP245 and 5% (–8 to 10%) for SSP585 scenarios during wet seasons. In the far future, monsoon flow will increase by 13% (0.4 to 23%) for SSP245 and 52% (–29 to 151%) under SSP245 and SSP585. A marginal change in winter flow was shown by –6% (–16 to 4%) reduction under SSP245 and –13% (–64 to 63%) under SSP585 reduction in the 2080s.

Azoxystrobin induced genotoxicity in Pethia conchonius, a freshwater fish of river Teesta, India

Azoxystrobin, a widely used fungicide, can contaminate water bodies through surface run-off, posing a risk to aquatic organisms. This study aimed to assess the genotoxic effects of azoxystrobin on the fish Pethia conchonius. The 96 h lethal concentration (LC50) of azoxystrobin was determined to be 0.514 mg/L. Based on LC50, three sub-lethal concentrations (SLCs) of 0.025 mg/L, 0.0514 mg/L, and 0.103 mg/L were used to expose fish for 96 h. The blood and gill samples were collected at 24 h intervals for analysis. The Micronucleus (MN) and Comet assays were used to evaluate nuclear abnormalities and DNA damage, respectively. The results showed that the frequency of nuclear abnormalities and DNA damage in the exposed groups was significantly higher than the control, with increasing concentrations and duration of exposure. The highest levels of micronuclei, notched and blebbed nuclei, and DNA damage parameters were observed in the group exposed to SLC III for 96 h. These findings indicate that azoxystrobin is highly genotoxic to fish causing severe DNA damage.

Importance based on avian diversity of Pakhibitan Bird &amp; Wildlife Sanctuary, Jalpaiguri District, West Bengal, India

A comprehensive inventory of faunal and floral species in a specific region holds significant value for scientific investigation. This study was conducted between 2015 and 2021, especially during the winter season, in Pakhibitan Bird &amp; Wildlife Sanctuary (also known as Gajoldoba wetland) in West Bengal, which was established in 2016. This wetland surrounded by forests is located on the upper section of the Teesta Barrage in the Dooars region of Jalpaiguri District, and it attracts birds from the Central Asian Flyway. Around 124 bird species belonging to 14 orders and 37 families were documented. Passeriformes with 32 species, and Anatidae with 23 species, are the most abundant groups. Based on the IUCN Red Data Book (2022–23), six species are Near Threatened, four are Vulnerable, and one Endangered. About 50% of birds were resident, 44% migratory, and 6% local migrants.

Unveiling the catastrophic landslide-induced flash flood in Teesta River, Sikkim: insight from South Lhonak Glacial Lake

Unveiling the catastrophic landslide-induced flash flood in Teesta River, Sikkim: insight from South Lhonak Glacial Lake

India-Bangladesh Conflict: An Overview

Abstract: The India-Bangladesh conflict primarily revolves around historical, territorial and resource-related disputes that have shaped the bilateral relationship between the two neighbouring South Asian countries. Emerging from the Partition of British India in 1947 and the subsequent creation of East Pakistan (now Bangladesh), tensions escalated during the 1971 Bangladesh Liberation War, which resulted in Bangladesh's independence with Indian military support. Key areas of conflict have included the demarcation of borders, particularly over the disputed enclaves, the maritime boundary in the Bay of Bengal, and the sharing of transboundary river waters, such as the Ganges and the Teesta. While the Land Boundary Agreement of 2015 resolved several border issues, the water-sharing disputes remain unresolved, particularly concerning the Teesta River, which is critical to Bangladesh’s agriculture. Additionally, non-traditional security concerns such as illegal migration, cross-border insurgencies, and trafficking continue to challenge bilateral relations. Nevertheless, India and Bangladesh have strengthened their cooperation in recent years, particularly in trade, energy and regional security, while both countries seek to balance their national interests within a framework of diplomacy and economic interdependence. This overview highlights that while conflict persists in certain areas, India and Bangladesh have made significant strides in resolving disputes and fostering collaboration, although challenges remain in ensuring equitable resource distribution and addressing mutual security concerns.

Source distribution, ecological risks, and controlling factors of heavy metals in river sediments: Receptor model-based study in a transboundary river basin

In the context of transboundary rivers, which constitute intricate fluvial ecosystems, the persistent threat of heavy metals (HMs) contamination poses significant risks to ecosystem health. In this study, ecotoxicological hazards, governing factors, and the distribution of nine HMs (uranium (U), lead (Pb), cadmium (Cd), nickel (Ni), chromium (Cr), manganese (Mn), iron (Fe), zinc (Zn), and copper (Cu)), as well as sediment characteristics (sand, silt, clay, organic matter, and pH) are assessed within the sediment. The current investigation encompasses the analysis of twenty-seven sediment samples, utilizing inductively coupled plasma mass spectrometry, in the transboundary river basin of Bangladesh, specifically the Teesta River. Notably, the findings underscore the predominance of Cd as a contaminant, responsible for 51.85%, 81.84%, and 100% of the geo-accumulation index, contamination factor, and enrichment factor, respectively. The Teesta River emerges as moderately to highly polluted, with cumulative probabilities of 7.4%, 85.2%, and 7.4% denoting “medium”, “high”, and “priority” pollution levels, respectively. Regions in the upstream and downstream middle sections of the study area exhibit relatively higher pollution levels, particularly in proximity to Kaunia Upazila in the Rangpur district. Ecologically, the potential risk index indicates a low likelihood of ecological impacts at 77.8%, alongside a moderate risk observation of 22.2%. The current results attribute the distribution of these HMs to the pH and organic matter content within the sediment, serving as pivotal factors. To unravel the origins of the HMs, the positive matrix factorization (PMF) model successfully identifies four contributing factors, primarily from geogenic sources. Validation of the PMF model through Spearmen correlation and principal component analysis (PCA) reveals a consistent pattern, affirming its efficacy in this analysis. Within the region, HM sources are identified as originating from anthropogenic activities such as irrigation, industrial discharges, and domestic effluent, in addition to substantial inputs from geogenic sources. Recognizing the transboundary nature of metal pollution, the current study underscores the imperative for continuous and vigilant monitoring, coupled with the implementation of robust management practices. The interplay of both anthropogenic and geogenic factors necessitates a comprehensive approach to effectively and sustainably combat HM contamination.

Investigating the changing land use patterns and their impacts on ecosystem in the Teesta River Basin

This study investigated the changing land use patterns and their impacts on ecosystem in the Teesta River Basin of northwestern Bangladesh. Although anthropocentric land use patterns, including agricultural land use, settlements, built areas, and waterbody loss, have been increasing in the Nilphamari district, by negatively affecting local ecosystems, they have not been identified by prior research. Limitations of contemporary literature motivated me to work on this crucial ground in the Teesta River Basin in Northwestern Bangladesh. This study applied a mixed research approach to identify the study objectives. Firstly, the land use and land cover (LULC) changes which occurred between 2000 and 2020 were detected using satellite imagery and supervised classification method. In addition to the detection of LULC changes, the study explored the people’s perceptions and experiences about the ecosystem changes resulted from the LULC changes over the last 20 years, conducting stakeholders’ consultations and household surveys utilizing a semi-structured questionnaire. The findings indicated that waterbodies in Nilphamari district have significantly decreased from 378 km2 in 2000 to 181 km2 in 2020. In the same way, the vegetation coverage has reduced 187 km2 between the years 2000 and 2020. On the contrary, agricultural lands (croplands) have increased from 595 km2 to 905 km2 and settlements have increased from 81 km2 to 206 km2 between the years 2000 and 2020. From the chi-square test, it was found a significant association between ecosystem change and biodiversity loss. It was further identified that waterbody decreases have significant impacts on aquatic ecosystems. The results of this study also indicated that due to the introduction of foreign tree species, local and native species have been significantly decreasing over the time. This study emphasizes the non-anthropocentric and inclusive land use policy implications for protecting life on land and preserving the aquatic ecosystem in Bangladesh.

Impact of Structural Interventions on Morphological Changes of Teesta River Using River Sensing Approach

Impact of Structural Interventions on Morphological Changes of Teesta River Using River Sensing Approach

Excess topography and outburst flood: Geomorphic imprint of October 2023 extreme flood event in the Teesta catchment of Eastern Himalayas

The 2023 South-Lohnak Lake outburst flood event across the upstream Teesta catchment triggered short-lived, high-magnitude flooding and substantial socioeconomic disruption downstream. We performed landscape analysis across the Teesta catchment using topographic metrics to understand the geomorphic response to this extreme flood event. We estimated the various topographic metrics such as ksn anomaly (normalized channel steepness index) (∼500–2500 m0.9), SL-index (stream-length gradient index) (∼5000–7000 m), and KsnQ (channel steepness-weighted discharge) along the trunk channel draining through the South-Lohnak Lake, which shows high magnitude in flooded regions and numerous spikes in their longitudinal profiles across mass-wasting regions downstream. We used the KsnQ metric as an event characteristic to investigate the changes in the channel morphology due to high-magnitude flooding. There was a sudden increase in the magnitude of the KsnQ metric when the river traversed through the Chungthang dam over the high ranges of excess topography (∼0–1700 m). This shows that the downstream channel morphology changes rapidly during this flood event, and KsnQ is a significant indicator of geomorphic change. To understand the spatial relationship between the physical drivers that trigger this outburst flood, we quantified the causal relationship between glacial-hydrological drivers over the upstream Zemu-sub catchment. Our observations suggest that precipitation intensity and surface temperature had a significant direct causal influence on snowmelt and snow depth (in terms of water equivalent) over the event duration with a 5-day and 1-day lag composite. Through the inclusion of lagged composites and causal linkages, the drivers across the glaciated landscape serve as event anomalies, which trigger the glacier hillslope failure and subsequent high-magnitude outburst flooding. Therefore, we suggest that the interaction of topographic discontinuity with hydrological extremes and their causal interdependencies influences this outburst event in the upper reaches, followed by high-magnitude flooding in the downstream reaches of the Teesta River. However, the long-term geomorphic consequences of such events on the evolution of the regional landscape remain unclear.

Application of wavelet-based multivariate long short-term memory models in prediction of stage for Teesta River, India

ABSTRACT River stage prediction is indispensably a challenging task in flood-prone river basins to disseminate accurate early warning in advance. In this study, multivariate wavelet-based long short-term memory (WLSTM) models have been developed to predict river stage at six gauging stations of the Teesta River basin in India for 1, 3, and 5-day lead time, the comparison of which has been done with long short-term memory (LSTM) models. Various combinations of wavelet decomposed components were utilized to form different sub-series that were fed as input in WLSTM models. In terms of statistical indicators, both the models yielded exceptionally good results, but the root-mean-square error values of the WLSTM model for 1- and 3-day lead time were minimal compared to the LSTM model. However, the accuracy of the LSTM model in longer lead time prediction is noticeable. Specifically, the WLSTM model predicted the peak stage values more precisely compared to the LSTM model, indicating the potential of wavelet analysis to capture the variations and periodicities of the data by removing the noise. Though the WLSTM model marginally outperformed the LSTM model in prediction accuracy, the results highlight both models as feasible alternatives for longer lead time water level prediction.

Understanding the impact of bridge structure on river morphology through geospatial techniques: case on Teesta River, Bangladesh

The primary priority of bridge construction over a waterway is to support and confirm constant communication. Conversely, it may locally disrupt the health of the river which will have an adverse influence on the hydrological as well as morphological behavior of nearby regions by way of the river’s narrowing. The current study evaluated the effect of bridge structure on river morphological characteristics for Teesta River. Hence to do, this work robbed two approaches. Firstly, the Landsat images from a pre-road bridge (2001 and 2006) and post-road bridge construction (2011, 2016, and 2021) are processed and used for bar formation and bank line shifting. Secondly, the bar properties, differences in channel width, and changes in river bank were evaluated using geospatial technology. The outcomes revealed a recurrent change of bar area and channel width at the upstream side of the bridges and likewise dominating at the downstream side. Throughout the post-road bridge period, the average bar area has increased noticeably by 32.45 sq.km which is 7.75% of the total river area and the downstream bar area has also increased considerably. Besides, both bank lines of the river were dominated by erosion in the post-road bridge construction era. Accordingly, the Teesta Road bridge’s existence has had a significant impact on the morphological modification in recent years. The study also reveals that the bars and islands of Teesta River undergo a drastic change and the river can be treated as a braided one, and also showed the minor trend of meandering. The findings of this research may be supportive for sustainable and long-term planning and development of the rivers and neighboring floodplains in Bangladesh.

Sensitivity Analysis of the Physiographic Parameters of the Teesta River Basin by Hydrological Modelling

Sensitivity Analysis of the Physiographic Parameters of the Teesta River Basin by Hydrological Modelling

PRESENT SCENARIO OF LIVESTOCK BREEDING AND MANAGEMENT PRACTICES IN THE NORTHERN PART OF BANGLADESH

&lt;p&gt;&lt;strong&gt;Background: &lt;/strong&gt;Bangladesh has a rich heritage of livestock rearing. The management and breeding practices differ across the country. &lt;strong&gt;Objectives:&lt;/strong&gt; To study the present scenario of breeding and management practices of livestock at northern Teesta river basin based Lalmonirhat district in Bangladesh. &lt;strong&gt;Methodology: &lt;/strong&gt;Total 100 farmers were selected using random sampling technique from 5 upazilas of Lalmonirhat district during July to December, 2022. Data were analyzed using SPSS 23.0 statistical package. &lt;strong&gt;Results: &lt;/strong&gt;Results showed that most of the farmers (65%) at the northern part of Bangladesh were middle-aged, 41% of them completed secondary education, and their occupation was mainly agriculture (55%). About 37.78% of respondents supplied roadside grass as roughage to their livestock. Maximum number of respondents (60.24%) supplied hand mixed feed as a source of concentrate whereas 39.76% of respondents used commercial feed. 96% of farmers practiced artificial insemination to inseminate their cows and heifers while in goat nearly all respondent farmers (98.41%) practiced natural mating. Among the breeding companies, 41.41% farmers preferred semen from the Bangladesh Rural Advancement Committee (BRAC), followed by Advanced Chemical Industries (ACI) (30.30%), Government (Department of Livestock Services (DLS) (22.22%), and others (6.07%). About 41.76% respondents used 50% Sahiwal - 50% local genotype bull to breed the cows whereas 23.08% respondents used 100% Sahiwal, 18.68% used 75% Holstein Friesian-25% local, 5.49% used 100% Holstein Friesian, 3.30% used 50% Holstein Friesian-50% Local and only 3.30% used 87.5% Holstein Friesian-12.5% Local genotype bull semen, respectively.&lt;strong&gt; &lt;/strong&gt;On the other hand, most of the farmers (98.41%) chosen Black Bengal breeding buck during breeding and remaining used crossbred (Black Bengal Goat- Jamunapari) to breed their does. The actual price of bull semen from Govt. (DLS) was 30 Bangladeshi Taka (BDT) on average for all the breeds whereas, the price ranged 110-200 BDT depending on cattle breeds and bull/bucks Identification (ID) in different private enterprises. Farmers had to pay on an average&lt;strong&gt; &lt;/strong&gt;181.18 BDT for DLS originated semen in addition to that BRAC Artificial Insemination (AI) workers took an average of 425.61 BDT from farmers to inseminate their cows. The average milk yield/d was 1.82±0.14, 3.35±0.40, and 2.74±0.27 liters for local, HF crossbred and Sahiwal crossbred respectively in that region. The prevalence of repeat breeding incidences was 13.74%, 14.21%, and 15.17%, for Local, Sahiwal crossbred, and Holstein Friesian crossbred genotypes respectively. The highest incidence of disease was found as Lumpy Skin Disease (14.67%) followed by Foot and Mouth Disease (FMD) (11.98%) and other parasitic and metabolic diseases. In the study area, it was found that maximum number of the respondents (95%) faced excessive feed price problem along with some other problems. &lt;strong&gt;Implications: &lt;/strong&gt;Government intervention is necessary to improve the situation of livestock production in the country. &lt;strong&gt;Conclusion:&lt;/strong&gt; This study showed the overall scenario of livestock production, breeding, and management in the northern part of Bangladesh which could be helpful for the govt., Non-governmental organizations (NGO’s) and policymakers to take realistic steps for the improvement of livestock production in the northern part of Bangladesh.&lt;/p&gt;

Flood susceptibility modelling of the Teesta River Basin through the AHP-MCDA process using GIS and remote sensing

Flood susceptibility modelling of the Teesta River Basin through the AHP-MCDA process using GIS and remote sensing