丹江口水库水环境变化特点及其改善对策

Water Environment Change and Its Improvement Countermeasures in Danjiangkou Reservoir Area

[目的]探讨南水北调中线工程运行后丹江口库区水环境变化影响因素及其防控对策,为削弱库区污染负荷,确保库区水质安全提供参考。[方法]以丹江口水库周围及上游流域为研究区域,采用前后对比分析法,分析水环境变化特征及其主要影响因素,从而提出保护改善水环境的对策。[结果]水库大坝蓄水后丹江库区水质总体良好但空间差异显著,部分入库支流和库湾局部污染较为严重,氮、磷和重金属元素含量较高。[结论]丹江口库周局部地区水土流失、农村点源污染、农业面源污染及人类活动是影响库区水质的主要原因。针对库区存在的生态环境问题,提出了继续稳定实施退耕还林/还草政策,优化农村产业结构,加强工矿企业排污监管,优化监控站点并加强居民环保意识的保护对策和建议。

[Objective]The influencing factors of water environment change and its improvement countermeasures in Danjiangkou reservoir area after the operation of the middle route of south-to-north water diversion project were studied in order to provide reference for reducing pollution load and ensuring water quality safety in the reservoir area.[Methods]Taking Danjiangkou reservoir and the upper reaches of the river basin as the study area,the characteristics of water environment change and its main influencing factors were analyzed by using the before and after comparison methods,and the countermeasures to protect and improve water environment were proposed.[Results]After impoundment of the dam,the water quality of Danjiang Reservoir area was generally good,but the spatial difference was significant.Some tributaries and bays were polluted seriously,and the contents of nitrogen,phosphorus and some heavy metals were high.[Conclusion]Soil and water loss,point source pollution in rural areas,non-point source pollution in agriculture and human activities are the main factors affecting water quality in Danjiangkou reservoir area.In view of the ecological environment problems existing in the reservoir area,the protection countermeasures and suggestions are proposed,such as continuous and stable implementation of the policy of returning farmland to forest or grassland,the optimization of the rural industrial structure,the strengthening of the supervision of industrial and mining enterprises’pollution discharge,the optimization of monitoring stations and the strengthenomg the residents'environmental protection awareness.