Understanding the water quality in mountainous rivers is critical for sustainable water resources management. By using the rivers’ self-purification to improve water quality is also the most economical and sustainable way to clean water. In the present study, the QUAL2KW model is applied to investigate the water quality and self -purification capacity in a mountainous river. The Abbasabad River in Iran is used as the study site. The river is divided into two interva ls based on the main purpose of water usage: drinking and agriculture. The model is calibrated and validated using field data from five monitoring stations along the river. Six parame ters, COD, BOD, DO, P-PO4, N-NO3, and N-NH4 are calculated and compared with field data. The Margin of Safety (MOS) is presented and added to the value of each parameter for better water resources protection. The sensitivity analysis is conducted to identify the m ost influential parameters in water quality simulation for mountainous rivers. It is revealed that the parameters of oxidation rate, nitrification rate, and denitrification rate have the maximum influence on water quality simulation for mountainous rivers using QUAL2KW. Additionally, three scenarios are tested for water quality and self-purification. It is found that the river flow rate has a stronger impact for water self - purification in mountainous rivers and the location of point-source pollution has very limited impact.

中文翻译：

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QUAL2KW对山区河流水质及自净的数值模拟

了解山区河流的水质对于可持续水资源管理至关重要。利用河流的自净作用来改善水质，也是最经济、最可持续的净水方式。在本研究中，QUAL2KW 模型用于调查山区河流的水质和自净能力。伊朗的阿巴萨巴德河被用作研究地点。这条河根据用水的主要目的分为两个区间：饮用和农业。该模型使用沿河五个监测站的现场数据进行校准和验证。计算了六个参数，COD、BOD、DO、P-PO4、N-NO3 和 N-NH4，并与现场数据进行比较。提供安全边际 (MOS) 并将其添加到每个参数的值中，以更好地保护水资源。进行敏感性分析以确定山区河流水质模拟中影响最大的参数。结果表明，氧化速率、硝化速率和反硝化速率参数对QUAL2KW山地河流水质模拟影响最大。此外，还测试了三种情况的水质和自我净化。研究发现河流流速对山区河流的水自净影响较大，而点源污染的位置影响非常有限。结果表明，氧化速率、硝化速率和反硝化速率参数对QUAL2KW山地河流水质模拟影响最大。此外，还测试了三种方案的水质和自净能力。研究发现河流流速对山区河流的水自净影响较大，而点源污染的位置影响非常有限。结果表明，氧化速率、硝化速率和反硝化速率参数对QUAL2KW山地河流水质模拟影响最大。此外，还测试了三种情况的水质和自我净化。研究发现河流流速对山区河流的水自净影响较大，而点源污染的位置影响非常有限。