猫跳河流域水质演化机理研究

Analysis of Water Quality Evolution Mechanism in the Maotiaohe Watershed

猫跳河流域是我国河流梯级水电开发的典范。在一段时期内,该流域水电开发为当地提供充足的电力资源和清洁的淡水资源。但在电站运行30多年里,该流域水质不断恶化,致使提供清洁淡水的功能丧失。研究水电开发的流域水质演化机理能为今后水电开发提供科学指导。首先,本文收集了1980年-2005年红枫湖和百花湖的总磷、总氮数据,对猫跳河流域水质恶化的态势进行分析。分析表明,自20世纪80年代以来,猫跳河流域水质经历了Ⅱ类-Ⅲ类-Ⅳ类-Ⅴ类的演化态势。其次,本文用红枫湖和百花湖的总磷、总氮数据与其上游地区的人类社会活动进行拟合,以探讨水电开发的流域水质恶化机理。拟合结果表明:①流域范围内人类活动频率加大(人口增长、城镇化水平提高、工业生产规模扩大)造成污水排放增多,是导致水质恶化的根本原因;②农村、城镇生活污水排放和化肥施用量的增长是流域水质恶化的直接原因,在这三个因子中,农村生活污水排放和化肥施用量的增长对流域水质恶化所起的作用最大。最后,本文对猫跳河流域水电开发、水质恶化以及水环境治理进行综合分析。分析表明,猫跳河流域经历了自20世纪50年代末-70年代的水电开发,到20世纪80年代-90年代的水质恶化,再到20世纪90年代中期至今的水环境治理过程,这一过程正是猫跳河流域水质演化的机理。

The Maotiaohe watershed is a typical mode of cascade hydropower development of rivers in China. Hydropower development has provided adequate power and clean water resources for the local areas over the past years. However, the water quality of the watershed has been deteriorative, which resulted in the loss of the clean freshwater provisioning function. Investigating the evolution mechanism of the water quality of the hydropower development can provide reasonable measures for the hydropower development in the future. First, total phosphorus and nitrogen data of Hongfeng Lake and Baihua Lake during the period 1980-2005 were collected for use in analyzing the deteriorating trend of the water quality in the study watershed. It was found that the watershed had experienced evolution trends of II-III-IV-V type since 1980. Second, correlation analysis of water quality data about Hongfeng Lake and Baihua Lake with data regarding social and economic situations for the upper reaches of the Maotiaohe River was performed to unravel mechanisms of water quality deterioration due to hydropower development. Results show that 1） extensive human activities in the upper reaches, involving an increasing number of population, the improvement of urbanization, and the extension of industrialization, are the primary causes of the water quality deterioration. 2） The discharge of sewage of rural residents and urban residents, and the growing use of chemical fertilizer are the direct causes for the water quality deterioration. Among the three major causes, the discharge of sewage of rural residents and the growing use of chemical fertilizer are the most significant factors making the water quality deteriorative. Finally, the authors made a comprehensive analysis of the hydropower development, the deterioration of water quality, and the water quality management. Results show that the Maotiaohe watershed has experienced hydropower development since the late 1950s. The deterioration of water quality occurred primarily from the 1980s to the 1990s. The water quality management was conducted from the mid 1990s to the present