农业面源污染视角下的三峡库区重庆段水资源的安全性评价——基于DPSIR框架的分析

Safety assessment of water resources in Chongqing Section of the Three Gorges Reservoir Area based on DPSIR model from the perspective of agricultural non-point pollution source

农业面源污染已成为我国流域污染的主要来源,并已威胁到城乡居民的饮水安全,影响社会经济的可持续发展.三峡库区是生态脆弱区,水资源安全对促进库区生态环境保护与区域经济社会和谐发展尤为重要.为探明三峡库区重庆段农业面源污染与流域水资源安全演进变化的过程与内在机制,根据DPSIR框架原理,运用结构方程模型进行分析,并评价了2000—2011年流域水资源安全程度.结果表明:流域水资源安全程度分为两个阶段,2000—2005年水资源安全等级从一般安全下降到很不安全,2005—2011年水资源安全等级从很不安全上升到安全,出现阶段变化的主要原因在于从2006年开始,政府认识到流域生态环境的重要性并加大了对农业面源污染的控制力度,加强了对水土流失的治理.因此,为有效地减缓农业面源污染、改善流域水体质量,需要调整农业经济发展方式和农业产业结构,依靠科学技术提高农业生产效率,降低农用化学药品的投入,推广有机农业、改善耕地质量;加强水资源监督管理,实施农业生产节水措施;进一步加强面源污染控制投入,有效控制水土流失程度以减缓面源污染,实现流域水资源安全可持续利用.

The agricultural non-point pollution source has become the major source of river basin pollution in China.It threatens the safety of urban and rural residents＇ drinking water and has some effects on the sustainable development of our economy.The Three Gorges Reservoir area is frangible ecotope.Therefore,water resource security is especially important for promoting the protection of ecological environment in this area and developing the regional economy.To explore the evolutionary process and inherent mechanism between agricultural nonpoint pollution source and river basin water resource security in Chongqing Section,this paper makes an assessment of river basin water resource security level over the period 2000—2011 by using structural equation model based on DPSIR frame.The results show that the river basin water resources security level can be divided into two stages.During 2000—2005 the water resources safety level was degraded from ＇generally secure＇ to ＇very unsecure＇.However,during 2005—2011 the security level was improved from ＇very unsecure＇ to ＇secure＇.The main cause of these changes is due to the fact that since 2006 the government has realized the importance of ecological environment and strengthened its control over agricultural nonpoint source pollution and soil erosion.Hence,to reduce agricultural nonpoint source pollution and improve river basin water quality,on one hand,the development way of agricultural economy and agricultural structure should be adjusted,depending on science and technology to improve the agricultural product efficiency,reduce the investment of agricultural chemicals and popularize organic agriculture to improve the quality of cultivated land;on the other hand,it is necessary to strengthen the supervision over the water resources,the reservation of water in agricultural production and the investment in the pollution control.By this way,soil erosion and nonpoint source pollution can be effectively controlled and reduced and the sustainable and safe use of river basin water resources can be achieved.