摘要:
通过对秦岭南坡中山地带火地塘林区大气降水与支沟溪流水和流域出口径流水质的比较分析,以及溪流水和流域出口径流水质与水量的相关分析,发现7~10月份大气降水呈微酸性,经过森林生态系统的调节,径流pH值升高,且不随流量变化而发生变化;森林生态系统对随降水输入的NO3-、NH4+、PO43-有很好的净化作用,这种作用对于降低南水北调中线工程取水地丹江口水库水质富营养化的威胁非常有益,对重金属元素Cd、Pb、Mn有固定作用;对K、Na、Ca、Mg、Fe有增加作用,尤其对Ca、Mg含量增幅较大,但这种作用不会对水质产生不良影响,对Fe的调升有利于水质改善;森林生态系统在调减Zn含量方面作用显著;林区径流水质与水量之间并无较大关系,水质不随水量变化而发生较大变化,森林生态系统对水质有很好的稳定作用。
关键词:
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南水北调
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秦岭
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森林生态系统
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水质
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影响
Abstract:
The objective of this research is to determine the effect of the forest ecosystem on water quality in the Huoditang Forest, part of the water supply catchment for the South-to-North Water Transfer Project.The effect of the forest on water quality was determined by measuring the water quality of rainfall and stream water collected from tributaries within the watershed and at the watershed outlet.The water flow rate in the streams was also taken into account.From July to October, rainfall was slightly acidic.The pH of the stream water was higher than that of the rainfall and was not affected by flow rate.The concentration of NO3-,NH4+, and PO43- in the stream water were lower than in the rainwater, indicating that the forest ecosystem was effective for reducing the level of these nutrients in water.This should reduce the probability of water eutrophication in the Danjiangkou Reservoir, the main water storage area for the South-to-North Project.The forest ecosystem also fixed the heavy metals Cd, Pb and Mn.This is helpful for improving water quality.The concentration of K, Na, Ca, Mg and Fe in the water increased as it passed through the region.The increases in Ca and Mg were especially large.The increases in K, Na, Ca and Mg have no effect on water quality, but the increase of Fe in the stream water improves drinking water quality.The forest ecosystem has the important function for reducing Zn in the water as it passes through the catchment area.There is no relationship between water quality and flow rate.Generally, there is no large change in water quality as flow rate varied.The results from this study show that the water quality is stabilized as it passes through the forest ecosystem.
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