Environmental status of Manahara River, Kathmandu, Nepal
Environmental status of Manahara River, Kathmandu, Nepal
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尼泊尔加德满都马纳哈拉河环境状况
DOI：
10.3126/bdg.v10i0.1417
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发表时间：
2008
期刊：
影响因子：
--
通讯作者：
N. Tamrakar
中科院分区：
文献类型：
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作者：
R. Bajracharya;N. Tamrakar
位于加德满都谷地东北部的马纳哈拉河在过去十年中受到若干人为活动和自然原因的干扰，从而使其娱乐功能和溪流栖息地恶化。为了获得河流的现有环境状况和扰动，对河流的栖息地、污染水平和地表水水质进行了调查。在5个代表性河段中，下游河段（Sano Thimi）被划分为中级，与上游河段相比，污染和环境恶化程度更严重。浑浊度、电导率、化学需氧量、生物需氧量和氨氮呈指数函数递增，溶解氧呈指数函数递减。除位于萨诺蒂米河段下游的Jadibuti桥下游外，还观察到Garra sp. （Buduna）、Schizothorax sp. （Asala）、Channa sp. （Hiele）和Heteropneustes sp. （Singe）等水生生物。Jadibuti地区鱼类种类稀少，可能是由于溶解氧减少（5 mg/l）。麻那原河的大肠菌群数量在3000 ~ 4000之间，显示出严重的细菌污染。影响麻那原河生境和地表水水质的主要干扰因素是河岸缓冲区的破坏、河沙的过量挖掘、洪泛区和沙洲的侵蚀、固体废物和污水排放以及土地利用变化的趋势。为了减缓因人为活动导致的玛那哈拉河环境恶化，地方政府需要立即采取行动。尼泊尔加德满都特里布万大学地质学院学报，2007年第10卷，第21-32页
The Manahara River located in northeast part of the Kathmandu Valley has been disturbed for last one decade by several anthropogenic activities and natural causes thereby deteriorating its recreational functions and stream habitat. To obtain an existing environmental condition and disturbances of the river, the river was surveyed for its habitat, pollution level and surface water quality. Among the five representative segments of the river, the downstream segment (Sano Thimi) was scored into intermediate category showing more pollution and environmental deterioration compared to the upstream segments. Turbidity, electrical conductivity, chemical oxygen demand, biological oxygen demand and ammonia increase, whereas dissolved oxygen decreases from upstream to downstream with exponential functions. Aquatic lives like Garra sp. (Buduna), Schizothorax sp. (Asala), Channa sp. (Hiele) and Heteropneustes sp. (Singe) were observed except in downstream of the Jadibuti Bridge situated downstream from Sano Thimi stretch. Fish species were rare from the Jadibuti area most probably due to reduced dissoved oxygen (5 mg/l). Coliform bacteria ranged from 3000 to 4000 in the Manahara River showing high amount of bacterial contamination. Major disturbances, which affect river habitat and surface water quality of the Manahara River were destruction of riparian buffer zones, excavation excessive amount of sand from the river, encroachment of floodplains and bars, solid waste and sewer effluent, and tendency of landuse change. To retard environmental degradation of the Manahara River from the human-induced activities, local government needs to take immediate action. doi: 10.3126/bdg.v10i0.1417 Bulletin of the Department of Geology, Tribhuvan University, Kathmandu, Nepal, Vol. 10, 2007, pp. 21-32