南水北调中线丹江口库区主要生态环境问题及植被恢复

Main Eco-Environmental Problems and Revegetation in the Danjiangkou Reservoir Water Supplying Area of the Middle Route of the South to North Water Transfer Project

丹江口水库作为南水北调中线引水渠,其水质好坏直接关系到工程效益的发挥。与工程实施相关的水质保障措施将在一定程度上控制水源地点源污染,非点源污染将成为水库水质污染的主要来源。目前库周边支流如老灌河、滔河等的水质为Ⅴ类或劣Ⅴ类,库区水质整体有逐年恶化趋势。2004-2005年库区断面监测结果表明：As、Cd、Cu、Pb和Zn的最大值已分别达到0.120 7、0.006、0.056 3、0.048、0.012 4 mg/L,均超出了Ⅱ类水标准限值,总氮范围为0.73-2.22 mg/L,其最大值达劣Ⅴ类。同时,严重的植被毁损及水土流失已危及库区安全。通过分析水源地面临的水质、植被损坏、水土流失等主要生态环境问题,提出了以异龄复层的乔灌混交林和草相结合为主的植被恢复和库岸带生态屏障建设等方式,来改善库区脆弱生态环境的途径和策略,并对植被合理搭配及土地利用方式进行探讨。

The Danjiangkou Reservoir is the water supplying area of the Middle Route of the South to North Water Transfer Project. Thus, its water quality is critical to the project. At present, water quality of tributaries near reservoir is level V or less than level V （i. e. , Tao river and Laoguan river）, and water quality is continuingly deteriorated and many trace metals have been detected in recent years. In the time period of 2004-2005, the max values of As, Cd, Cu, Pb and Zn were 0. 1207, 0. 0060, 0. 0563, 0. 0480 and 0. 0124mg/L respectively, and total nitrogen, from 0. 73-2.22 mg/L, was one of the main pollutants in the reservoir. Simultaneously, degraded vegetation and soil erosion have already endangered the environment of the Danjiangkou Reservoir region. By analyzing water quality, vegetation degradation, water and soil erosion in the reservoir, the strategy for revegetation of the mixed forests of tree, shrub and grass, and riparian ecosystem restoration has been put forward to improve fragile environment.