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The article discusses the study which describes the areas of bank erosion that causes heavy loss of land by Brahmaputra river at the Kaziranga National Park in Assam,India. It uses geographic informations systems (GIS to analyze sequential changes in banklines of the river and geomorphology to characterize the irver, while changes in time over spaces are measured using Sol topographic maps. It shows that the main cause of erosion at the river is the loose non-cohesive sediments of the bank.

Yarlung Zangbo River is one of the most important rivers in the southwest river source area, it is the longest plateau river in China, the cradle of the birth and development of Tibet civilization, and also an international water system. It is of great significance to study its water resources utilization and water environment protection. This paper compared different river extraction methods, including the normalized difference water index, multi-band spectral correlation threshold method, maximum likelihood classification method and object-oriented classification method, based on Landsat images, and combined with remote sensing and GIS technologies. The study area is Yarlung Zangbo River, one of the main rivers in southwest river source region. Meanwhile, river changes have been analysed based on upstream and midstream of Yarlung Zangbo River extracting results of four images in different periods. The result shows that object-oriented classification method has advantage of removing mountain shadow, its accuracy of river extraction is the highest, and Yarlung Zangbo River area shows a decreasing trend from 2000 to 2016, and there are some changes of watercourse in midstream as well. [ABSTRACT FROM AUTHOR]

Guwahati, identified with the ancient Pragjyotishapura, has been a major centre of cultural development in Assam since ages. The present day Guwahati is well known for the temple of Kamakhya, the early medieval sites like Pandunath, Vishnu-Janardhan in the southern bank; Umananda and Urvashi Islands in middle of the river and Dirgheswari, Daul Govinda, Kurma-Janardan, Aswaklanta, Rudreswar and Manikarneswar in the northern bank of Brahmaputra river. The famous archaeological site of Ambari in Guwahati has provided ample evidence for understanding the cultural growth of the area since the beginning of Common Era. Considering the archaeological and historical significance of Guwahati, a detailed documentation and in-depth study has been taken up by the authors in various areas of the city and this paper is an attempt to document the archaeological remains in the Rajaduar area in North Guwahati. [ABSTRACT FROM AUTHOR]

A forecasting lead time of 5-10 days is desired to increase the flood response and preparedness for large river basins. Large uncertainty in observed and forecasted rainfall appears to be a key bottleneck in providing reliable flood forecasting. Significant efforts continue to be devoted to developing mechanistic hydrological models and statistical and satellite-driven methods to increase the forecasting lead time without exploring the functional utility of these complicated methods. This paper examines the utility of a data-based modeling framework with requisite simplicity that identifies key variables and processes and develops ways to track their evolution and performance. Findings suggest that models with requisite simplicity--relying on flow persistence, aggregated upstream rainfall, and travel time--can provide reliable flood forecasts comparable to relatively more complicated methods for up to 10 days lead time for the Ganges, Brahmaputra, and upper Meghna (GBM) gauging locations inside Bangladesh. Forecasting accuracy improves further by including weather-model-generated forecasted rainfall into the forecasting scheme. The use of water level in the model provides equally good forecasting accuracy for these rivers. The findings of the study also suggest that largescale rainfall patterns captured by the satellites or weather models and their "predictive ability" of future rainfall are useful in a data-driven model to obtain skillful flood forecasts up to 10 days for the GBM basins. Ease of operationalization and reliable forecasting accuracy of the proposed framework is of particular importance for large rivers, where access to upstream gauge-measured rainfall and flow data are limited, and detailed modeling approaches are operationally prohibitive and functionally ineffective. [ABSTRACT FROM AUTHOR]

The Brahmaputra River of South Asia is the fourth largest river in the world in terms of annual discharge. The lower Brahmaputra River basin is susceptible to catastrophic flooding with major social, economic, and public health impacts. There is relatively little rainfall and snowpack information for the watershed, and the system is poorly understood hydrologically. Using a combination of available remotely sensed and gauge data, this study analyzes snow cover, rainfall, and monsoon period discharge for a 14-yr time period (1986–99). It is found that interannual rainfall variability is low and is a weak predictor of monsoon discharge volumes. Strong evidence is found, however, that maximum spring snow cover in the upper Brahmaputra basin is a good predictor of the monsoon flood volume. Despite the temporal and spatial limitations of the data, this study’s analysis demonstrates the potential for developing an empirical tool for predicting large flood events that may allow an annual early window for mitigating flood damages in the lower Brahmaputra basin, home to 300 million people. [ABSTRACT FROM AUTHOR]

Arsenic occurs in three common allotrops namely metallic grey, yellow and black. Arsenic founds in shallow aquifer of Ganga and Brahmaputra River Basin. Arsenic contamination in groundwater in the Ganga-Brahmaputra basin in India is reported as arsenic contaminated zone. There are seven highly contaminated states namely-West Bengal, Jharkhand, Bihar, Uttar Pradesh (UP), Assam, Manipur and Chhattisgarh in India. Three districts namely Ballia, Gazhipur and Varanasi in UP are contaminated with very high amount of arsenic. In Ballia district 5 out of 17 blocks are highly contaminated and people are suffering by skin disease related to arsenic. The results depicted that extent amount of arsenic is found in eastern part of Ballia District. The objective of this paper is to study the extent and magnitude of arsenic in groundwater for almost all shallow, medium and deep aquifer of Murli Chhapra Block. Results showed 78% samples are contaminated with arsenic. The contamination rate is in decreasing order by going down(shallow>medium>deep aquifers). In the study area more than 80 percent people have their own hand pump ranged between 12mto 25m in shallow aquifer. [ABSTRACT FROM AUTHOR]

Three species of fishes, viz., Bagarius yarrelli, Parambassis lala, listed Near Threatened and Hemibagrus menoda, Least Concern by IUCN, respectively belonging to the families Sisoridae, Ambassidae and Bagridae have been newly recorded from the upper reaches of the Brahmaputra and Surma-Megna river basins of Meghalaya. Diagnostic characters and brief notes on the habitat ecology of the fishes are given in this paper. [ABSTRACT FROM AUTHOR]

The Yarlung Zangbo River (YZR) is the largest river system in the Tibetan Plateau, and its basin is one of the centers of human economic activity in Tibet. Large uncertainties exist in several previous climate change studies in this basin because of limited climate observations. In this paper, we used a meteorological drought index (Standardized Precipitation Evapotranspiration Index, SPEI) and a newly-released gridded climate forcing dataset based on high-quality climate station data to re-evaluate climate change in the YZR Basin during the period of 1961-2014. Results showed that precipitation experienced a statistically insignificant increasing trend at a rate of 6.32 mm/10 years, and its annual mean was 512.40 mm. The basin was sensitive to climate change in terms of the air temperature that significantly increased at the rate of 0.32 °C/10 years. This warming rate was obviously larger than that in many other regions. Analysis of SPEI showed that the basin had no obvious statistical trends in the number of dry/wet episodes, but the severity of dry episode aggravated in terms of duration and magnitude. This study provides a reliable analysis of climate change in the YZR Basin, and suggests this large Tibetan river basin is sensitive to climate change. [ABSTRACT FROM AUTHOR]

This paper communicates the extension of the distribution range of Batasio merianiensis in Sille River in the upper Brahmaputra drainage, East Siang District, Arunachal Pradesh. Detailed examinations of the specimens revealed existence of few morphological variations against those reported by Heok Hee Ng in 2009 on the following characteristics: by having a longer preanal (70.4-73.4 vs. 66.3-68.2% SL); a longer prepectoral (25.1-29.3 vs. 21.4-25.7% SL); a longer adipose-fin base (22.0-27.6 vs. 16.9-22.2% SL); a shorter post-adipose distance (11.6-13.4 vs.13.4-15.5% SL); a deeper body at anus (depth 18.3-20.8 vs.15.2-18.4% SL) and broader head (width 17.6-20.0 vs.13.5-16.2 % HL). Few additional characters of the fish are included along with brief information on its habitat. The LlPUM, the semi-traditional method of fishing in the river is identified as a major threat to this species. [ABSTRACT FROM AUTHOR]

The potential ability of an ensemble prediction system (EPS) to represent its own varying forecast error provides strong motivation to produce an EPS over a less expensive deterministic forecast. Traditionally, this ability has been assessed by correlating the realized forecast error with the ensemble's dispersion. This paper revisits the limitations of the skill-spread correlation, but uses aspects of the correlation to introduce two metrics to assess an EPS's capacity to provide a reliable likelihood of its own error. Using a perfect EPS, skill-spread correlation is shown to be limited by its dependence on how 'skill' and 'spread' are defined and, perhaps most fatally, by its inability to distill the skill-spread reliability from the stability properties of the physical system being modeled. Building from this, it is argued there are two aspects of an ensemble's dispersion that should be assessed. First, is there enough variability in the dispersion to justify the expense of the EPS? The factor that controls the theoretical upper limit of the spread-error correlation can be useful in diagnosing this. Second, does the variable dispersion of an ensemble relate to a variable expectation of the forecast error? Representing the spread-error correlation in relation to its theoretical limit can provide a simple diagnostic of this attribute. A context for these concepts is provided by assessing two operational ensembles: western U.S. temperature forecasts and Brahmaputra River flow before and after postprocessing. It is shown that 'skill-spread' reliability can be improved by postprocessing to that of a perfect EPS, but at the cost of the potential information content of the EPS's variable dispersion. [ABSTRACT FROM AUTHOR]

This paper extends the range of distribution of Conta pectinata in Sille River, Brahmaputra drainage, East Siang District of Arunachal Pradesh and gives some information on its habitat and threats, which are still to be documented properly. Some brief additional characters are also added here. Our examination revealed that some morphological variations exists from originally described C. pectinata by having deep body at anus (10.3-11.9 vs. 7.5-9.4% SL); short dorsal-spine (length 15.7-20.8 vs. 20.9-24.0% SL), less number of serrae on anterior margin of dorsal-spine along the entire length (15-18 vs. 18-20) etc. The major threats identified are the frequent use of electrocution and the chemicals in the river during the winter season. [ABSTRACT FROM AUTHOR]

In light of the new cooperative water development agreements in South Asia since 1996 and, in particular, the 1996 Ganges Waters Treaty between India and Bangladesh, this paper explores the geopolitical obstacles to cooperation between states in the joint development of large-scale river systems and current opportunities for successful development. The general problems of cooperation faced by the riparian states which share successive rivers are examined with reference to the geopolitical obstacles to cooperation in the Bengal delta since the Partition of the Indian subcontinent through which India and Pakistan gained Independence as separate states in 1947. Against the background of repeated attempts to resolve water-sharing issues between India and East Pakistan and its successor state, Bangladesh, this paper concludes that for cooperation to succeed contemporary large-scale river development has to meet a wide range of criteria which go beyond conventional engineering or economic cost-benefit analyses to include geopolitical criteria. These range from global-scale environmental concerns to micro-scale issues of mutual regional benefit. This paper proposes a major new development on the Brahmaputra and Ganges which the authors argue could break the log-jam of a zero-sum game approach to surface water development in the Bengal delta. Unlike most large-scale dam-building proposals, the barrage construction outlined would cause negligible population displacement, and making maximum use of existing river channels would minimize the environmental impacts associated with the large canal or dam construction envisaged in earlier Ganges–Brahmaputra–Meghna (GBM) schemes. Yet the paper also recognizes that while such a proposal could bring economic, environmental and political advantages to all users in the GBM basin, new thinking on the management of international rivers is less in favour of supply-side solutions, and the case would need to be... [ABSTRACT FROM AUTHOR]

Climate change is expected to raise river discharge and sea level in the future, and these near-term changes could alter the river flow regime and sedimentation pattern of future floods. Present hazard assessment studies have limitations in considering such morpho-dynamic responses in evaluating flood hazards or risks. Here, we present a multi-model-based approach to quantify such potential hazard parameters influenced by climate change for the most vulnerable communities living on river bars and islands of the Brahmaputra–Jamuna River. River flood-flow and flood wave propagation characteristics are predicted to be affected by changing temporal distribution patterns of precipitation as a result of enhanced global warming. Increased incidences of large multi-peak floods or uncommon floods resulting in long-duration floods driven by sea-level rise may happen as a result of this. To assess it, we have set up a hydromorphic model, Delft3D, for the Brahmaputra–Jamuna River forced by upstream flow, generated from a hydrological model SWAT, over the Brahmaputra basin. The simulations cover moderate, wettest, and driest conditions of the RCP8.5 scenario, and the results reflect the flooding consequences of the near-future, mid-century, and end-century. Floods in the Brahmaputra–Jamuna River are becoming more severe, frequent, and long-lasting, as a result of climate change, and are expected to last until the end of November rather than the current September timeline. While assessing the hazard, we found that the pattern and timing of the flood are as equally important as the peak of the flood, as the river continuously adjusts its cross-sectional area with the flow. The study also demonstrates that, depending on their location/position, climate-induced hazards can affect sand bars/islands disproportionally. The high flood depth, duration, and sedimentation have a significant impact on the sand bars downstream of the river, making them more vulnerable. [ABSTRACT FROM AUTHOR]

Recent advances on power, politics, and pathways in climate change adaptation aim to re-frame decision-making processes from development-as-usual to openings for transformational adaptation. This paper offers empirical insights regarding decision-making politics in the context of collective learning through participatory scenario building and flexible flood management and planning in the Eastern Brahmaputra Basin of Assam, India. By foregrounding intergroup and intragroup power dynamics in such collective learning spaces and how they intersect with existing micropolitics of adaptation on the ground, we examine opportunities for and limitations to challenging entrenched authority and subjectivities. Our results suggest that emancipatory agency can indeed emerge but is likely to be fluid and multifaceted. Community actors who are best positioned to resist higher-level domination may well be imbricated in oppression at home. While participatory co-learning as embraced here might open some spaces for transformation, others close down or remain shut. [ABSTRACT FROM AUTHOR]

The randomness in morphology of the Brahmaputra River is very common because of its high flow variability and erodible banks. The river is severely braided with no permanent bank line and varies its width by 1.2 km to 18 km. During the monsoon season it follows several tortuous braided paths to dissipate its enormous energy. The river changes its braided planform in response to seasonal water and sediment waves and makes its morphology extremely complex. This paper aims to link the braided planform disorderness as a measure of entropy with the energy dissipated by the braided river system to study the river behaviour for various flood waves. [ABSTRACT FROM AUTHOR]

Abstract: The Jamuna River is the downstream continuation of the Brahmaputra in Bangladesh. It is one of the largest sand-bed braided rivers in the world and every year it erodes thousand hectares of mainland floodplain, rendering tens of thousands of people landless and/or homeless. Understanding the morpho-dynamics of this river and its responses to the various drivers of morphological change that act on it is essential to improving the livelihoods of millions of floodplain dwellers in Bangladesh, especially given the threats posed by climate change. Reliable data, information and knowledge of river process are sparse and so progress in linking the impacts of multiple drivers (including neo-tectonics, earthquakes, large-scale avulsions and engineering interventions) to complex morphological responses depends on making best use of historical maps, time-series satellite images, hydro-morphological data, expert judgment and local knowledge. This paper draws on all these sources to chronicle the morphological evolution of the Jamuna River since the avulsion that created it about 200years ago, and to establish temporal trends and spatial patterns in the changes that have characterized process–response mechanisms in this fluvial system since then. The understanding gained from these investigations then supports deeper analyses to: explain how historical migration of the river westward has produced significant contrasts between left and right (west) bank material properties; elucidate the relationships between discharge, fluvial processes, anabranch instability and floodplain erosion rates, and; identify causal links between drivers and morphological responses at a variety of time and space scales. Finally, the new knowledge generated by the analyses developed herein are combined with existing, conceptual and empirical process–response models for the Jamuna to predict possible future morphological adjustments in ways helpful in identifying appropriate strategies for climate change adaptation in Bangladesh. The enhanced knowledge gained from these historical and contemporary investigations may also be useful in assessing the impacts of natural and anthropogenic drivers on other large, braided rivers. [Copyright &y& Elsevier]

Riverbank erosion is a global problem with significant socio-economic impacts. Microbially induced calcite precipitation (MICP) has recently emerged as a promising technology for improving the mechanical properties of soils. The present study investigates the potential of selectively enriched native calcifying bacterial community and its supplementation into the riverbank soil of the Brahmaputra river for reducing the erodibility of the soil. The ureolytic and calcium carbonate cementation abilities of the enriched cultures were investigated with reference to the standard calcifying culture of Sporosarcina pasteurii (ATCC 11859). 16S rRNA analysis revealed Firmicutes to be the most predominant calcifying class with Sporosarcina pasteurii and Pseudogracilibacillus auburnensis as the prevalent strains. The morphological and mineralogical characterization of carbonate crystals confirmed the calcite precipitation potential of these communities. The erodibility of soil treated with native calcifying communities was examined via needle penetration and lab-scale hydraulic flume test. We found a substantial reduction in soil erosion in the biocemented sample with a calcite content of 7.3% and needle penetration index of 16 N/mm. We report the cementation potential of biostimulated ureolytic cultures for minimum intervention to riparian biodiversity for an environmentally conscious alternative to current erosion mitigation practices. [ABSTRACT FROM AUTHOR]

Groundwater is a renewable natural resource and dynamic groundwater resource is the part which is recharged annually and exploited largely. The study area is situated on the southern bank of River Brahmaputra. The main source of groundwater recharge in the area is precipitation. The study is an attempt to evaluate the groundwater dynamic resource potential by quantifying the gross annual natural groundwater recharge and to find out the stage of development of groundwater in the area for a better planning and development. Water table fluctuation method, rainfall infiltration factor method and empirical methods have been applied for the quantitative evaluation of the dynamic groundwater resource potential in the area. A point recharge zone map was prepared in GIS by the interpolation of thirteen years data on average fluctuation values. The result obtained by point recharge zone method using groundwaterlevel fluctuation & specific yield data gives a more realistic assessment of groundwater recharge, which is found to be 484 MCM. The stage of groundwater development is found to be less than 70% and no longterm decline in groundwater levels has been observed. The study area comes under the safe area category and the groundwater potentiality in the area is found to be very good. [ABSTRACT FROM AUTHOR]

Watershed discharge (WD) in the alpine regions, such as the upper reach of Yarlung Zangbo River Basin (YZRB), China, could have changed severely in response to climate changes. Yet, how hydrometeorological variables varied at different time scales and how WD varied in response to hydrometeorological variables in the alpine regions remained questions to be answered. The ensemble empirical mode decomposition (EEMD) method was employed in this study to investigate the nonlinear climate change trends (averaged and extreme states) and the associated multiscale impacts on WD variations over the upper reach of the YZRB during 1961–2009. All investigated hydroclimatic variables, i.e., precipitation, temperature, and WD, were found to be varied nonlinearly with clear multiscale oscillations characterizing great differences in the oscillation periods, corresponding significance levels, and variance contribution rates, among which precipitation posed a weak impact on WD variations, while temperature played a significant role in WD fluctuations. Furthermore, among all temperature extremes, the dominant index affecting WD variations was TXm (annual mean of the daily maximum temperature) but not TXx (annual maximum of the daily maximum temperature) at both interannual and interdecadal scales, which might be caused by that TXx increased evapotranspiration and reduced WD. A significant correlation between temperature (both averaged and partial extreme states) and annual WD at both interannual and interdecadal scales indicated that a synchronous change existed between them. The present study provided first insight into how hydrometeorological variables varied at different time scales and how WD fluctuated in response to hydrometeorological variables over the upper reach of the YZRB, China. [ABSTRACT FROM AUTHOR]

The Brahmaputra River flows through Assam, India, for about 670 km along an alluvial valley as a wide braided river. The width of the river varies with time along its course. The braiding intensity of this river is estimated using the braiding index (BI) of Brice (1964), which also changes with space and time along the course of the river. Temporal changes of both width and BI have been studied using topographic maps of 1912-1928 and 1963-1975, and dry season satellite data of 1996, 2000, 2007 and 2009. The mean widths of the Brahmaputra River channel in Assam during 1912-1928, 1963-1975, 1996, 2000, 2007 and 2009 were 5949 m, 7455 m, 7505 m, 8008 m, 8308 m and 9012 m, respectively, confirming an overall increase in width with time. Both the width and variation of width are lowest in four short narrower segments of the river. Three of these segments represent hard points comprising gneissic rock, and one segment is on alluvium comprising cohesive clay. The increase in width is correlated to enormous sediment load produced by the great Assam earthquake of 1950 and large-scale deforestation in the Himalayas. The mean BIs for the Brahmaputra for 1963-1975, 1996, 2000, 2007 and 2009 were 8.59, 8.43, 6.67, 6.58 and 7.70, respectively, indicating in general a decreasing trend up to 2007. The BI showed low variation at the four narrow segments where there is also a minimum variation of the channel width. The BI has increased significantly in the upstream part of the river. Very high fluctuation of discharge (17,000 m³/s-1 in 24 h) and high sediment loads of the Brahmaputra (daily mean sediment discharge of 2.0 million tonnes during monsoon), erodible alluvial banks and high width/depth ratios are the main causes of development of braiding. The interrelationship between channel width and BI of the Brahmaputra shows a positive correlation, indicating an increase in BI with increasing channel width. [ABSTRACT FROM AUTHOR]

Future hydrological extremes, such as floods and droughts, may pose serious threats for the livelihoods in the upstream domains of the Indus, Ganges, Brahmaputra. For this reason, the impacts of climate change on future hydrological extremes is investigated in these river basins. We use a fully-distributed cryospheric-hydrological model to simulate current and future hydrological fluxes and force the model with an ensemble of 8 downscaled General Circulation Models (GCMs) that are selected from the RCP4.5 and RCP8.5 scenarios. The model is calibrated on observed daily discharge and geodetic mass balances. The climate forcing and the outputs of the hydrological model are used to evaluate future changes in climatic extremes, and hydrological extremes by focusing on high and low flows. The outcomes show an increase in the magnitude of climatic means and extremes towards the end of the 21st century where climatic extremes tend to increase stronger than climatic means. Future mean discharge and high flow conditions will very likely increase. These increases might mainly be the result of increasing precipitation extremes. To some extent temperature extremes might also contribute to increasing discharge extremes, although this is highly dependent on magnitude of change in temperature extremes. Low flow conditions may occur less frequently, although the uncertainties in low flow projections can be high. The results of this study may contribute to improved understanding on the implications of climate change for the occurrence of future hydrological extremes in the Hindu Kush–Himalayan region. [ABSTRACT FROM AUTHOR]

Determination of the erodibility parameters, such as critical shear stress and erodibility coefficient, are necessary before estimating the annual bank erosion (or bank retreat) at river reaches. However, in many cases, the river site is inaccessible making it difficult to assess the soil parameters either by in situ tests or by laboratory experiments. In this study, Genetic Algorithm (GA)-based optimisation technique was used to estimate the erodibility parameters of middle reaches of the Brahmaputra River in India. Two approaches were followed. At first, erodibility parameters were estimated using daily stage records at a selected site. Secondly, based on the annual observed bank erosions (bank retreat) from satellite images, erodibility parameters were estimated in three different river reaches. All these results were compared with that from a previous study using in situ jet tests. Annual bank erosions (bank retreat) were estimated using the median values of the erodibility parameters. The results agree well with the average observed annual bank erosion of these river reaches. In addition, the effects of measurement errors and optimisation algorithms on the parameter estimation were analysed. Sensitivity analysis of the parameters in GA was evaluated and it was found that GA can be utilised in the data-scarce regions to estimate the average erodibility parameters. [ABSTRACT FROM AUTHOR]

The plankton and semi-plankton samples collected from four floodplain lakes (beels) of Barpeta district of lower Brahmaputra river basin, Assam state, northeastern India (NEI) revealed eighteen rotifer species of biodiversity and biogeographic interest belonging to five families and six genera. One species is new to the Indian Rotifera and one species is new to Assam. Our collections are characterized by two Australasian elements, five Oriental endemics, seven paleotropical species, and one cosmo (sub) tropical species. Nine species, restricted to date to NEI, are examples of regional distribution importance in India while six species depicted disjunct distribution in the country. Interestingly, seven species are categorized as Eastern hemisphere elements. All the taxa are illustrated to warrant validation as an increasing magnitude of 'unverifiable records' is a serious impediment for the progress of rotifer biodiversity in India. [ABSTRACT FROM AUTHOR]

This article examines the likelihood of water insecurity causing war between China and India. Water insecurity itself will not likely lead to armed conflict. But when coupled with other international and domestic factors, it could increase the likelihood of war. China's water scarcity and its widening north-south water gap have increased pressure to execute controversial water diversion plans. These plans will threaten India, especially since the Brahmaputra River flows through a disputed area. These factors, plus changing domestic conditions in China, may increase the likelihood of war. [ABSTRACT FROM AUTHOR]

Plankton samples collected from Deepor Beel (a Ramsar site), during July 2011 to June 2013, revealed 155 species of Rotifera, belonging to 35 genera and 20 families. Of these, 16 species belonging to eight genera and seven families are new records to the rotifer fauna of this wetland of northeast India. Our observations raise the total richness of the phylum known till date from this important floodplain lake (beel) of the Brahmaputra river basin to 171 species and thus highlight its biodiversity value as one of the globally rich Rotifera habitats. The updated list is interesting for following meta-analyses of rotifer occurrence in this only well sampled freshwater ecosystem of the Indian sub-region. [ABSTRACT FROM AUTHOR]

We investigate how the climate models contributing to the PCMDI/CMIP3 dataset describe the hydrological cycle over four major South and Southeast Asian river basins (Indus, Ganges, Brahmaputra and Mekong) for the 20th, 21st (13 models) and 22nd (10 models) centuries. For the 20th century, some models do not seem to conserve water at the river basin scale up to a good degree of approximation. The simulated precipitation minus evaporation (P -E), total runoff (R) and precipitation (P) quantities are neither consistent with the observations nor among the models themselves. Most of the models underestimate P - E for all four river basins, which is mainly associated with the underestimation of precipitation. This is in agreement with the recent results on the biases of the representation of monsoonal dynamics by GCMs. Overall, a modest inter-model agreement is found only for the evaporation and inter-annual variability of P - E. For the 21st and 22nd centuries, models agree on the negative (positive) changes of P - E for the Indus basin (Ganges, Brahmaputra and Mekong basins). Most of the models foresee an increase in the inter-annual variability of P - E for the Ganges and Mekong basins, thus suggesting an increase in large low-frequency dry/wet events. Instead, no considerable future change in the inter-annual variability of P - E is found for the Indus and Brahmaputra basins. [ABSTRACT FROM AUTHOR]

The Bagrid Catfish Mystus tengara was described from a pond located in India under the genus Pimelodus. The validity of the fish has been confused and has frequently been treated as a synonym of Mystus vittatus. In this study, the species is rediagnosed and redescribed on the basis of fresh material collected from the Ganga-Brahmaputra drainage. M. tengara is diagnosed from congeners in having a unique combination of the following characters: body with a distinct tympanic spot and four brown stripes which are separated by a pale narrow interspace; origin of adipose-fin not reaching the base of the last dorsal-fin ray, 31-42 gill rakers on first branchial arch, eye rounded with a diameter 19.0-23.8 % HL and dorsal spine length 12.3-17.2 % SL, maxillary barbel length 254.5-360.5 % HL. A key for the identification of Mystus species from Ganga-Bramaputra drainage is also provided. [ABSTRACT FROM AUTHOR]

The silver hatchet chela, Chela cachius (Hamilton, 1822), is a cyprinid freshwater species, commercially important for both subsistence and artisanal fisheries in Bangladesh. This study describes the length-weight relationship (LWR), length-length relationship (LLR) and the condition of this minnow species from the Old Brahmaputra River in Bangladesh. In this study, 12 monthly samples totalling 2400 specimens (1172 male; 1228 female) collected from November 2004 to October 2005 were used to conduct this study. For each individual, the total length (TL), fork length (FL) and standard length (SL) as well as body weight (BW) were measured. The overall sex ratio showed no significant difference from the expected value of 1:1 and the analysis of covariance (ANCOVA) revealed no significant difference between LWRs of male and female for the pooled data over a year. Parameters of LWRs of combined gender varied monthly with high coefficients of determination (r² > 0.751; p < 0.001). All the LLRs (SL vs. FL, FL vs. TL and SL vs. TL) exhibited strong correlations (r² > 0.886; p < 0.001) and ANCOVA analyses further indicated that LLRs did not differ between males and females. The relative-condition factors with regard to both months and SLs varied in all gender groups. Females maintained similar mean condition throughout life and showed more plumpness than both males and combined genders in all months. Finally, the results should be useful for the sustainable management of this minnow species in Old Brahmaputra River and adjacent water-bodies. [ABSTRACT FROM AUTHOR]

A new cyprinid species, Garra kalpangi is described from the Kalpangi River (Brahmaputra basin) in Arunachal Pradesh, India. The species is closely similar to G. gravelyi, G. rotundinasus and G. elongata in having a shared character i.e. a weakly developed proboscis. It is distinguishable from G. gravelyi for the absence of indistinct black spot at the bases of branched dorsal fin rays and lateral stripes on the side of the body. However, G. rotundinasus possesses lateral stripe along the lateral line. Further, the absence of transverse groove at the tip of snout and longitudinal black band in medial coudal fin differentiated it from G. elongata. The detail comparative account of the 16 available species of northeastern India confirmed its distinct diagnosis as a new species under the genus. Accordingly, after thorough investigation, the taxonomic keys for all the available species under the genus from the region have also been erected in this article. [ABSTRACT FROM AUTHOR]

Background: The number of outbreaks of HPAI-H5N1 reported by Bangladesh from 2007 through 2011 placed the country among the highest reported numbers worldwide. However, so far, the understanding of the epidemic progression, direction, intensity, persistence and risk variation of HPAI-H5N1 outbreaks over space and time in Bangladesh remains limited. Methodology/Principal Findings: To determine the magnitude and spatial pattern of the highly pathogenic avian influenza A subtype H5N1 virus outbreaks over space and time in poultry from 2007 to 2009 in Bangladesh, we applied descriptive and analytical spatial statistics. Temporal distribution of the outbreaks revealed three independent waves of outbreaks that were clustered during winter and spring. The descriptive analyses revealed that the magnitude of the second wave was the highest as compared to the first and third waves. Exploratory mapping of the infected flocks revealed that the highest intensity and magnitude of the outbreaks was systematic and persistent in an oblique line that connects south-east to north-west through the central part of the country. The line follows the Brahmaputra-Meghna river system, the junction between Central Asian and East Asian flyways, and the major poultry trading route in Bangladesh. Moreover, several important migratory bird areas were identified along the line. Geostatistical analysis revealed significant latitudinal directions of outbreak progressions that have similarity to the detected line of intensity and magnitude. Conclusion/Significance: The line of magnitude and direction indicate the necessity of mobilizing maximum resources on this line to strengthen the existing surveillance. [ABSTRACT FROM AUTHOR]

The article presents a study that determines the findings of the participatory research process designed to identify responses for sustainable water management in a climate change in the upper Danube and Brahmaputra river basins. It describes the method used in the study in which socio-economic vulnerability was investigated and analyzed. The result of the study validates the motivations which triggered the design of the project, leading to the development of the twinning of the river basin.

The article presents a study that examines options to mitigate climate change impact for the adaptive integrated water resources management (IWRM) in the upper Danube and Brahmaputra river basins. It explores the method of the study that analyzes several options that can effective reduce climate change impact in the two river basins. The result of the study indicates that effectiveness of the twinning of the two river basins in reducing the effects of climate change.

The article presents a study that determines the vulnerability of the people to the climate change in upper Brahmaputra and Danube river basins. It cites the Human Dimension of the Twinning European and South Asian River Basins to Enhance Capacity and Implement Adaptive Management Approaches Project (EC-Project BRAHMATWINN) aimed at developing socio-economic tools for the effective inclusion of the assessment. The study uses stakeholder inputs to identify weightings of vulnerability domains.

The article presents a study that describes the development of a set of integrated indicators to support integrated water resources management (IWRM) and climate change in the upper Brahmaputra and Danube river basins. It explores the objective of the study, designed to provide stakeholders with update on the trends of the river basins and water resources and quantify the effects of climate change. The findings of the study indicate a strong link between the main issues that affect the basin.

The article presents a study that determines the effectiveness of integrated hydrological modeling in assessing the effect of climate change on the water balance via Danubia model. It explores the method of the study that employs the Danubia model to calculate the water balance components under different conditions in the large-scale mountain water sheds of the upper Danube and Brahmaputra. The findings of the study reveal the effectiveness of the model in assessing climate change effects.

The article presents a study that evaluates the effectiveness of the regional climate model COSMO-CLM in determining regional climate projections in the upper Danube and Brahmaputra river basins. It explores the method of the study in which the model was post-processed by statistical means to provide accurate data. The findings of the study reveal an increase of temperature in both basins and for all seasons.

The article presents a study that examines the performance of the integrated water resources management (IWRM) in the upper Brahmaputra and Danube river basins. The study uses insights and knowledge from several scientific disciplines comprised of natural, socio-economic, and engineering sciences. The result of the study indicates that the IWRM method is part of water management planning and a good example for the implementation of the European Union (EU) water framework directive (WFD).

Heavy metal (Fe, Mn, Zn, Cu, Ni, Pb, and Cd) concentrations and their chemical speciations were investigated for the first time in bed sediments of Bharali River, a major tributary of the Brahmaputra River of the Eastern Himalayas. Levels of Fe, Mn, Pb, and Cd in the bed sediments were much below the average Indian rivers; however, Cu and Zn exhibit levels on the higher side. Enrichment factors (EF) of all metals was greater than 1 and a higher trend of EF was seen in the abandoned channel for most metals. Pb showed maximum EF of 32 at site near an urban center. The geoaccumulation indices indicate that Bharali river is moderately polluted. The metals speciations, done by a sequential extraction regime, show that Cd, Cu, and Pb exhibit considerable presence in the exchangeable and carbonate fraction, thereby showing higher mobility and bioavailability. On the other hand, Ni, Mn, and Fe exhibit greater presence in the residual fraction and Zn was dominant in the Fe-Mn oxide phase. Inter-species correlations at three sites did not show similar trends for metal pairs indicating potential variations in the contributing sources. [ABSTRACT FROM AUTHOR]

Climate change is likely to have significant effects on the hydrology. The Ganges-Brahmaputra river basin is one of the most vulnerable areas in the world as it is subject to the combined effects of glacier melt, extreme monsoon rainfall and sea level rise. To what extent climate change will impact river flow in the Brahmaputra basin is yet unclear, as climate model studies show ambiguous results. In this study we investigate the effect of climate change on both low and high flows of the lower Brahmaputra. We apply a novel method of discharge-weighted ensemble modeling using model outputs from a global hydrological models forced with 12 different global climate models (GCMs). Our analysis shows that only a limited number of GCMs are required to reconstruct observed discharge. Based on the GCM outputs and long-term records of observed flow at Bahadurabad station, our method results in a multi-model weighted ensemble of transient stream flow for the period 1961--2100. Using the constructed transients, we subsequently project future trends in low and high river flow. The analysis shows that extreme low flow conditions are likely to occur less frequent in the future. However a very strong increase in peak flows is projected, which may, in combination with projected sea level change, have devastating effects for Bangladesh. The methods presented in this study are more widely applicable, in that existing multi-model streamflow simulations from global hydrological models can be weighted against observed streamflow data to assess at first order the effects of climate change for specific river basins. [ABSTRACT FROM AUTHOR]

The breach of the eastern embankment of the Koshi Barrage at Paschim Kusaha Village of Sunsari District on 18 August 2008, created havoc for wildlife and their habitats, as well as people's livelihood and welfare. The Koshi River flowed through the breach for five months. Following the breach, a population assessment survey of the Endangered Ganges River Dolphin Platanista gangetica gangetica was made between March and November 2009 in the Koshi River main channel starting from Chatara to 2km south of Koshi Barrage to ascertain their status. A direct count survey was conducted by two teams of researchers simultaneously searching for animals by boat from Chatara to the Koshi Barrage including the Triyuga River and on foot along the river banks downstream of Koshi Barrage and along the Mariya River. Standard protocols were followed to record the number of sighted dolphins. A total of 11 dolphins were recorded in the entire 49-km river stretch with an encounter rate of 0.23 dolphins per km. The current result showed an encouraging population of dolphins in the Koshi Tappu Wildlife Reserve and its buffer zone but the threats for conservation still remain challenging. Close monitoring of dolphins and their habitats involving local communities are required for long term conservation of the river dolphins in Nepal. [ABSTRACT FROM AUTHOR]

A new species of the genus Badis Hamilton is described from Dibru River, Dibrugarh, Brahmaputra basin in Assam, India. The species has the following combination of characters: a conspicuous black blotch covering the superficial part of the cleithrum above pectoral fin base, a small oval-shaped black blotch on the middle of caudal fin, two predorsal bones, interorbital width 9.9-15.0, upper jaw length 6.1-6.9, lower jaw length 7.1-8.3 and orbital diameter 7.6-9.4 % SL. The species differs from its nearest congeners, B. badis, B. kanabos and B. tuivaiei by the absence of dark black or brown vertical bars on sides. A key to species of Badis of India is provided. [ABSTRACT FROM AUTHOR]

Garra arupi, a new cyprinid fish species is differentiated from its congeners along the base of the Himalaya in Brahmaputra basin by a combination of characters: two pairs of barbels, anterior position of vent (vent to anal distance 52.6-60.0% pelvic to anal distance), a band of 6-9 prominent horny tubercles on the tip of the snout, a submarginal black band on the dorsal fin, and 16 circumpeduncular scales. It is similar to G. kempi in having an anterior position of the vent, and similar to G. lissorynchus in having a distinct submarginal band on the dorsal fin. Garra arupi differs from G. kempi in having 35-36 (vs. 40-42) lateral line scales, 11-12 (vs. 13-14) predorsal scales, 16 (vs. 12) circumpeduncular scales, the presence of a distinct submarginal band on the dorsal fin (vs. absence), the presence of a transverse band of tubercles on the snout tip (vs. absence), and the presence of 7-8 thin stripes on the caudal peduncle (vs. absence). Garra arupi differs from G. lissorynchus in having 11-12 (vs. 14-15) predorsal scales, 7 (vs. 6) branched dorsal fin rays, 5 (vs. 4) branched anal fin rays, the absence of a W-shaped color band on the caudal fin (vs. presence), the absence of a rostral lobe on the snout (vs. presence), the presence of a transverse band of tubercles on the snout tip (vs. absence), and a vent to anal distance 52.6- 60.0 (vs. 37.3-40.2 %) pelvic to anal distance. [ABSTRACT FROM AUTHOR]

Guwahati, the lone city on the bank of the entire midstream of the Brahmaputra River, is facing acute civic problem due to severe depletion of water quality of its natural water bodies. This work is an attempt towards water quality assessment of a relatively small tributary of the Brahmaputra called the Bharalu River flowing through the city that has been transformed today into a city drainage channel. By analyzing the key physical, chemical and biological parameters for samples drawn from different locations, an assessment of the dissolved load and pollution levels at different segments in the river was made. Locations where the contaminants exceeded the permissible limits during different seasons were identified by examining spatial and temporal variations. A GIS developed for the watershed with four layers of data was used for evaluating the influence of catchment land use characteristics. BOD, DO and total phosphorus were found to be the sensitive parameters that adversely affected the water quality of Bharalu. Relationship among different parameters revealed that the causes and sources of water quality degradation in the study area were due to catchments input, anthropogenic activities and poor waste management. Elevated levels of total phosphorus, BOD and depleted DO level in the downstream were used to develop an ANN model by taking total phosphorus and BOD as inputs and dissolved oxygen as output, which indicated that an ANN based predictive tool can be utilized for monitoring water quality in the future. [ABSTRACT FROM AUTHOR]

The 26 December 2004 Indian Ocean tsunami damaged severely most of the Gulf of Bengal's coastal areas, but the coast of Bangladesh which stands at the edge of an extraordinarily extended continental shelf. This latter feature has been built through huge discharges of river sediments along the Brahmaputra and Ganges rivers. As a result of this enormous discharge, another interesting feature of the area is the deep underwater Canyon, connected with the estuaries, running NE-SW from 25 km off the coast towards the continental slope. We investigate here how these two geological features may have modified/perturbed the Indian ocean tsunami propagation and impact on the Coast of Bangladesh. For that purpose we have realized an ensemble of numerical simulations based on Funwave Boussinesq numerical model and a validated coseismic source. It is found, at first order, that the extended shallow bathymetric profile of the continental shelf plays a key role in flattening the waveform through a defocussing process while the Canyon delays the process. The wave evolution seems to be related at first order to the bathymetric profile rather than to dynamical processes like nonlinearity, dispersion or bottom friction. [ABSTRACT FROM AUTHOR]

The rotifer communities of 15 acidic - alkaline and soft - marginally hard water floodplain lakes of the lower Assam valley of the Brahmaputra river basin, characterized by low ionic concentrations, reveal 164 species (178 taxa) belonging to 39 genera and 20 families and represent the richest biodiversity known to date in these ecotones of the Indian subcontinent. Nine species are new to the Indian Rotifera. Cosmopolitan (59.7%)>pantropical (15.2%)>cosmotropical (12.2%) species dominate the taxocoenosis. Biogeographically interesting elements constitute a notable component (13.4%); important members of this category include six Oriental, two Australasian and seven Palaeotropical species. The examined fauna depicts a tropical character with predominance ofLecanespp. (28.0%). Littoral or periphytic rotifers (76.2%) dominate the planktonic species. Rotifers comprise a dominant qualitative (67-103, 79.1?±?11.0 species) and an important quantitative (mean: 41.1-65.9%) component of zooplankton in all floodplain lakes, register a moderate diversity (mean: 2.036-2.642), low dominance (mean: 0.019-0.216) and high evenness (mean: 0.840-0.893). The examined material indicates several interesting acidophilous elements. Richness depicts significant inverse correlation with pH. Water temperature, conductivity, dissolved oxygen and alkalinity record significant direct relationships with the rotifer abundance. Diversity is influenced by abundance and is also directly correlated with water temperature and conductivity. Canonical analysis shows a notable cumulative impact of six abiotic factors on richness, density and diversity. [ABSTRACT FROM AUTHOR]

The dry-wet transition is of great importance for vegetation dynamics, however the response mechanism of vegetation variations is still unclear due to the complicated effects of climate change. As a critical ecologically fragile area located in the southeast Qinghai-Tibet Plateau, the Yarlung Zangbo River (YZR) basin, which was selected as the typical area in this study, is significantly sensitive and vulnerable to climate change. The standardized precipitation evapotranspiration index (SPEI) and the normalized difference vegetation index (NDVI) based on the GLDAS-NOAH products and the GIMMS-NDVI remote sensing data from 1982 to 2015 were employed to investigate the spatio-temporal characteristics of the dry-wet regime and the vegetation dynamic responses. The results showed that: (1) The spatio-temporal patterns of the precipitation and temperature simulated by the GLDAS-NOAH fitted well with those of the in-situ data. (2) During the period of 1982–2015, the whole YZR basin exhibited an overall wetting tendency. However, the spatio-temporal characteristics of the dry-wet regime exhibited a reversal phenomenon before and after 2000, which was jointly identified by the SPEI and runoff. That is, the YZR basin showed a wetting trend before 2000 and a drying trend after 2000; the arid areas in the basin showed a tendency of wetting whereas the humid areas exhibited a trend of drying. (3) The region where NDVI was positively correlated with SPEI accounted for approximately 70% of the basin area, demonstrating a similar spatio-temporal reversal phenomenon of the vegetation around 2000, indicating that the dry-wet condition is of great importance for the evolution of vegetation. (4) The SPEI showed a much more significant positive correlation with the soil water content which accounted for more than 95% of the basin area, implying that the soil water content was an important indicator to identify the dry-wet transition in the YZR basin. [ABSTRACT FROM AUTHOR]

The Yarlung Zangbo River basin ecosystem is fragile. The distribution and transportation of phosphorus is of great significance for aquatic environmental protection and ecological security. The sequential extraction method and molybdenum antimony anti-spectrophotometry were used to measure the concentrations of different forms of phosphorus in the surface sediments from 15 sampling sites along the middle reaches of the Yarlung Zangbo River and its tributaries. The results show that the total phosphorus concentration in the surface sediments is 194.0~540.7 mg/kg, which is mainly composed of inorganic phosphorus. The concentrations of various phosphorus forms ranked as calcium-bound phosphorus (355.6 ± 86.0 mg/kg) > soluble phosphorus (15.9 ± 10.0 mg/kg) > iron-bound phosphorus (12.4 ± 12.3 mg/kg) > organic phosphorus (9.6 ± 6.1 mg/kg) > occluded phosphorus (9.2 ± 3.8 mg/kg) > aluminum-bound phosphorus (5.4 ± 2.3 mg/kg). On the whole, phosphorus concentration is greater in wet season than dry season. Regarding the spatial distribution characteristics, there are great disparities in the different forms of phosphorus in the middle reaches of the Yarlung Zangbo River. Comprehensive analysis shows that phosphorus of this area is mainly self-generated, and concentration of bioavailable phosphorus is small, demonstrating there will not be a large release. We also drew a "specific triangle" of the different forms of phosphorus concentrations in the research area and defined the "α" angle to determine the nutrient status of the overlying water quickly and effectively. Finally, phosphorus flux of the mainstream was estimated. This research may provide information on the phosphorus of Plateau Rivers. [ABSTRACT FROM AUTHOR]