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In the light of a growing demand for energy, the government of India has decided to tap into the potential of rivers by building numerous hydroelectric plants, with a view to doubling the amount of energy produced by water. One of the regions in which such plants are being built is the basin of the River Teesta (as a right-bank tributary of the Brahmaputra). The main aim of this article has been to present chemical-composition characteristics and physico-chemical parameters of water in the Teesta in its Himalayan course, with account being taken of the role the newly-built reservoir plays in shaping the chemistry of water in the river. Fieldwork entailed measurement of physico-chemical parameters of the water, as well as sampling for the purposes of chemical analysis. This was done in the post-monsoon period in the years 2013-2015. Sampling and measuring points were located along the Teesta in the Darjeeling Himalaya, over a length of approximately 43 km, between the borders of Sikkim and West Bengal and the southern margin of the Himalayas. Above the newly-built reservoir, measurements were made at points P1 and P2; while within it, measurements were made and samplings taken in the centre (at P3 by the shore). The two points located below the dam were P4 and P5. The results of the analysis of main physico-chemical properties and chemical compositio data for the water in the Teesta allowed conclusions as detailed in the following points to be drawn. The decrease in water temperature caused by the reservoir is slight, at approximately 1.0°C, with the indication being that very weak thermal stratification has developed, due to the rapid exchange of water in the reservoir. As for Total Dissolved Solids, marked stability of values across a narrow range is to be observed. The values for ANC in turn indicate that there is no risk of acidification at any point along the section examined. The newly-built reservoir is responsible for a decrease in concentrations of most of the main ions (i.e. Cl– , K+, Na+, Mg2, NO3 and PO4 3–). The reverse trend was only to be observed in respect of Ca2+, SO4 2– and NH4 +. The dam does not influence F– concentrations. The reservoir causes minor enrichment of water in ions of most metals like Cu, Ni, Zn, Cr, C and Sr. The more limited enrichment of water in the Teesta below the dam indicates self-purification processes taken place in the Teesta Reservoir where metals are concerned. The changes in physico-chemical properties and concentrations of ions caused by the reservoir are usually normalised by environmental factors before the Teesta exits the Himalayas (i.e. within 15 km of the reservoir). The results of the study are relevant, in light of the construction of several further reservoirs in the Teesta catchment in the near future, which can lead to significant transformations of the natural environment, including hydrochemical changes that determine water quality.
1. Abrahim G.M.S., Parker R.J., 2008, Assessment of heavy metal enrichment factors and the degree of contamination in marine sediments from Tamaki Estuary, Auckland, New Zealand, Environmental Monitoring and Assessment, 136, 1-3, s. 227-238. ; 2. Acharyya S.K., 1980, Structural framework and tectonic evolution of the Eastern Himalaya, Himalayan Geology, 10, s. 412-439. ; 3. Allan J.D., Castillo M.M., 2007, Stream Ecology: Structure and Function of Running Waters, Springer Science & Business Media. ; - ; 4. Bhattacharyya K., Mitra G., 2012, Geometry and kinematics of the Darjeeling-Sikkim Himalaya, India: Implications for the evolution of the Himalayan Fold-Thrust Belt, EGU General Assembly Conference Abstracts, 14, 4226. ; 5. Bi S.P., An S.Q., Liu F., 2001, A practical application of Driscoll's equation for predicting the acid-neutralizing capacity in acidic natural waters equilibria with the mineral phase gibbsite, Environment International, 26, 5, s. 327-333; doi: 10.1016/S0160-4120(01)00008-3. ; - ; 6. Birch G.F., Olmos M.A., 2008, Sediment-bound heavy metals as indicators of human influence and biological risk in coastal water bodies, ICES, Journal of Marine Science, 65, 8, s. 1407-1413. ; - ; 7. Bookhagen B., Burbank D.W., 2010, Towards a complete Himalayan hydrological budget: The spatiotemporal distribution of snow melt and rainfall and their impact on river discharge. Journal of Geophysical Research-Earth Surface, 115 (F3); doi:10.1029/2009jf001426. ; - ; 8. CISMHE (Centre for Inter Disciplinary Studies of Mountain and Hill Development), 2006, Carrying Capacity Study of Teesta Basin in Sikkim. Volume IV: Water Environment, New Delhi. ; 9. Champion H.G., Seth S.K., 1968, A Revised Survey of Forest Types of India, Manager Publications, New Delhi. ; 10. Chapman D.V. (red.), 1996, Water Quality Assessments: A Guide to the Use of Biota, Sediments, and Water in Environmental Monitoring, 2nd ed., UNESCO, World Health Organization, United Nations Environment Programme, London. ; 11. Fairchild G.W., Velinsky D.J. 2006, Effects of small ponds on stream water chemistry, Lake and Reservoir Management, 22, s. 321-330. ; - ; 12. Galy A., France-Lanord C., Derry L.A., 1999, The strontium isotopic budget of Himalayan rivers in Nepal and Bangladesh, Geochimica et Cosmochimica Acta, 63, s. 1905-1925. ; - ; 13. Gao Y., Wang B., Liu X., Wang Y., Zhang J., Jiang Y., Wang F., 2013, Impacts of river impoundment on the riverine water chemistry composition and their response to chemical weathering rate, Frontiers of Earth Science, 7, s. 351-360. ; - ; 14. Grumbine R.E., Pandit M.K., 2013, Threats from India's Himalaya dams, Science, 339, 6115, s. 36-37. ; - ; 15. Hannan H.H., 1979, Chemical modifi cations in reservoir-regulated streams, [w:] J.V. Ward, J.A. Stanford (red.), The Ecology of Regulated Streams, Springer US, s. 75-94. ; 16. Harrison J.A., Maranger R.J., Alexander R.B., Giblin A.E., Jacinthe P.A., Mayorga E., Wollheim W.M., 2009, The regional and global significance of nitrogen removal in lakes and reservoirs, Biogeochemistry, 93, 1-2, s. 143-157. ; 17. Hem J.D., 1985, Study and Interpretation of the Chemical Characteristics of Natural Water, 2254, Department of the Interior, US Geological Survey. ; 18. Hemond H.F., 1990, Acid Neutralizing Capacity, Alkalinity, and Acid-Base Status of Natural Waters Containing Organic Acids, Environmental Science and Technology, 24, 10, s. 1486-1489. ; - ; 19. Livingstone D.A., 1963, Chemical Composition of Rivers and Lakes, US Government Printing Office, Washington. ; 20. Mahanta C., Subramanian V., 2004, Water quality, mineral transport and sediment biogeochemistry, [w:] V. Singh, N. Sharma, C.S.P. Ojha (red.), The Brahmaputra Basin Water Resources, 47, Springer Science & Business Media, s. 376-400. ; 21. Murray J.A., Bochin N.A., 1973, Instructions for Compilation of the Chapter on Catastrophic Floods for the UNESCO Publication "Annual Summary of Information on natural Disasters", Forms with Explanatory Notes, UNESCO, Paris. ; 22. Nikanorov A.M., Brazhnikova L.V., 2009, Types and Properties of Water, 2: Water Chemical Composition of Rivers, Lakes and Wetlands, Encyclopedia of Life Support Systems. ; 23. Palmer R.W., O'Keeffe J.H., 1990, Downstream effects of impoundments on the water chemistry of the Buffalo River (Eastern Cape), South Africa, Hydrobiologia, 202, s. 71-83. ; - ; 24. Piper A.M., 1944, A graphic procedure in the geochemical interpretation of water analyses, Eos, Transactions American Geophysical Union, 25, 6, s. 914-928. ; - ; 25. Prokop P., Płoskonka D., 2014, Natural and human impact on the land use and soil properties of the Sikkim Himalayas piedmont in India, Journal of Environmental Management, 138, s. 15-23. ; - ; 26. Reuss J.O., Johnson D.W., 1986, Acid Deposition and the Acidifi cation of Soils and Water, Eological Studies, 59, Springer. ; - ; 27. Rigacci L.N., Giorgi A.D., Vilches C.S., Ossana N.A., Salibián A., 2013, Effect of a reservoir in the water quality of the Reconquista River, Buenos Aires, Argentina, Environmental Monitoring and Assessment, 185, 11, s. 9161-9168. ; - ; 28. Sharma S.K., Subramanian V., 2008, Hydrochemistry of the Narmada and Tapti Rivers, India, Hydrological Processes, 22, 17, s. 3444-3455. ; - ; 29. Singh A.K., Mondal G.C., Singh P.K., Singh S., Singh T.B., Tewary B.K., 2005, Hydrochemistry of reservoirs of Damodar River basin, India: weathering processes and water quality assessment, Environmental Geology, 48, 8, s. 1014-1028. ; - ; 30. Singh S.K., Sarin M.M., France-Lanord C., 2005, Chemical erosion in the eastern Himalaya: Major ion composition of the Brahmaputra and δ 13C of dissolved inorganic carbon, Geochimica et Cosmochimica Acta, 69, 14, s. 3573-3588. ; - ; 31. Soja R., Wiejaczka Ł., 2014, The impact of a reservoir on the physicochemical properties of water in a mountain river, Water and Environment Journal, 28, 4, s. 473-482; doi: 10.1111/wej.12059. ; - ; 32. Starkel L., Basu S. (red.), 2000, Rains, Landslides and Floods in the Darjeeling Himalaya, INSA, New Delhi. ; 33. Subramanian V., 2004, Water quality in south Asia, Asian Journal of Water, Environment and Pollution, 1, 1-2, s. 41-54. ; 34. Vörösmarty C.J., Fekete B.M., Tucker B.A., 2004, Monthly mean river discharge at gauging station Anderson Bridge, doi: 10.1594/PANGAEA.218327. ; 35. Zhao Q., Liu S., Deng L., Yang Z., Dong S., Wang C., Zhang Z., 2012, Spatio-temporal variation of heavy metals in fresh water after dam construction: a case study of the Manwan Reservoir, Lancang River, Environmental Monitoring and Assessment, 184, 7, s. 4253-4266. ; -