Length-length relationships of elongate glass perchlet, Chanda nama (HAMILTON, 1822) from the old Brahmaputra river, Bangladesh

The generalized length-length relationships of Chanda nama ((Hamilton, 1822) belongs to Ambassidae were studied separately for a period of a calendar year collected from the Old Brahmaputra River, Mymensingh, Bangladesh for male, female and combined populations. A total of 1170 specimens were examined where 599 were male and 571 were female. The standard length, fork length and total length of male ranged from 19 to 79 mm, from 23 to 90 mm, and 28 to 100 mm respectively. The standard length, fork length and total length of female were found from 15 to 81 mm, 24 to 89 mm, and from 29 to 100 mm respectively. The generalized relationships of standard length and fork length, fork length and total length, and standard length and total length of male, female and combined populations were FL = 1.08 SL+1.41, TL = 1.11 FL + 1.54 and TL = 1.20 SL+2.81; FL = 1.09 SL+1.23, TL = 1.12 FL+1.04 and TL = 1.22 SL+2.22; and FL = 1.09 SL+1.20, TL = 1.11 FL+1.27 and TL = 1.22 SL+2.38 respectively. The coefficient of determination (R2) revealed high values in all regression analyses. In length–length relationships, the coefficient of determination (R2) ranged from 0.973-0.990. The present findings of this study will be helpful for a well-organized and significant exploitation and regulation of the Chanda nama fishery in the Old Brahmaputra River and surrounding ecosystems. Res. Agric., Livest. Fish.8(3): 339-347, December 2021

A Mass Balance Approach in Sediment Budgeting of Large Alluvial Rivers with special emphasis on the Brahmaputra in Assam

Morphology of an alluvial river channel is the consequence of erosion, sediment transport and sedimentation in a river. Sediment budget accounts for the sources, sinks and redistribution pathways of sediments, solutes and nutrients in a unit region over unit time. Human activities are the most important factors that affect the variation in the pattern of river sediment load. This paper discusses sediment budget of a few large rivers by review of literature and estimation of sediment budget of Brahmaputra River in Assam using mass balance approach. An attempt has also been made to discuss human and climatic impact on sediment load of major rivers of the world. Total sediment load in the Brahmaputra River at downstream location (India-Bangladesh border) was estimated to be 814×106 t/year. Considering 10% of sediment load of the Brahmaputra as bed load, suspended sediment load at downstream was estimated to be 733×106 t/year. Tributaries, bank erosion and scouring of river bed were found to contribute 52%, 27% and 21% respectively to sediment load of Brahmaputra at downstream locations. In spite of limitations of the dependable data, future complexity due to climate change impact and hydropower dam initiative in upstream of the River, the study is a simplified approach in sediment budgeting of the Brahmaputra.

Commodities trade, river transport and colonialism: The Brahmaputra river valley in the nineteenth century

The article seeks to show how Assam’s riverine environment, and its natural resources, generated and inflected a process of commercialisation in the nineteenth century. Historically, present-day Assam was connected to the rest of the world through the Brahmaputra river and its tributaries. In the early decades of colonial rule, plants such as caoutchouc and tea were discovered in the valley. These developments, together with transportation networks built with state and private capital, heralded a new phase of commerce in the region. A rich scholarship in South Asian history has shown how the river played a crucial role in the economic changes in different regions. The article belongs in that scholarship but stresses the role of the river as an artery of transportation rather than as an agricultural resource. The river system facilitated Assam’s closer integration with the world economy and the colonial regime.

Assessing the Water Pollution of the Brahmaputra River Using Water Quality Indexes

Water quality is continuously affected by anthropogenic and environmental conditions. A significant issue of the Indian rivers is the massive water pollution, leading to the spreading of different diseases due to its daily use. Therefore, this study investigates three aspects. The first one is testing the hypothesis of the existence of a monotonic trend of the series of eight water parameters of the Brahmaputra River recorded for 17 years at ten hydrological stations. When this hypothesis was rejected, a loess trend was fitted. The second aspect is to assess the water quality using three indicators (WQI)–CCME WQI, British Colombia, and a weighted index. The third aspect is to group the years and the stations in clusters used to determine the regional (spatial) and temporal trend of the WQI series, utilizing a new algorithm. A statistical analysis does not reject the hypothesis of a monotonic trend presence for the spatially distributed data but not for the temporal ones. Hierarchical clustering based on the computed WQIs detected two clusters for the spatially distributed data and two for the temporal-distributed data. The procedure proposed for determining the WQI temporal and regional evolution provided good results in terms of mean absolute error, root mean squared error (RMSE), and mean absolute percentage error (MAPE).