滇池草海水污染治理工程措施及其防治效果评估

在滇池流域"六大工程"治理体系的共同作用下,近年来滇池外海和草海水质整体改善明显,草海作为滇池蓄清排污的载体功能已逐步转变为居民休闲娱乐场所和城市名片。为适应草海功能定位的转变并加快敏感湖区的水质改善,近期实施了牛栏江—草海应急补水工程、新老运粮河水体净化生态工程和海埂大堤水体置换通道工程,其中新老运粮河水体净化生态工程实现了草海湖区清污水的物理隔离和清污分流,牛栏江—草海应急补水工程为环湖截污和草海的清污分流提供了必要的水资源条件,海埂大堤水体置换通道工程进一步缩短了清流区的水体置换周期并为环境敏感区的水景观质量提供了动力学保障;从水质改善效果来看,清污分流可使清流区TN、TP指标水质改善15%～28%,水体置换通道工程将改善草海的内源累积状况并有利于草海水质持续向好的方向演变,并通过工程联合调度可促使草海水质持续向好发展。

Study on the engineering measures and prevention effect of Caohai water pollution in Dianchi Lake

Under the joint action of six-key-project management system in Dianchi Lake basin, the water quality of the Waihai and Caohai in Dianchi Lake has been improved significantly in recent years. Caohai, the carrier for pollutant discharge in Dianchi Lake, has been gradually transformed into a place of leisure and entertainment for residents and name card for the city. In order to adapt to the orientation of the func-tional change of Caohai and accelerate the water quality improvement in the sensitive Lake areas, new eco-project was implemented, such as emergency water supply project of Niulan River-Caohai, new eco-puri-fication project of Laoyunliang River and water replacement channel project of Haigeng levee. The clean and sewage water was physically isolated and separated through new eco-purification project of Laoyunliang River. The emergency water supply project of Niulan River-Caohai provided the necessary water resources conditions for intercepting pollution around the lake and separating clean and sewage water. Water replace-ment channel project of Haigeng levee shortened the water replacement period in the clean water area and provided hydrodynamic guarantee for water landscape in environmental sensitive areas. As the result, the TN and TP were reduced by 15%~28%. Water replacement channel project will improve the internal accu-mulation condition and be conductive to the continuous improvement of water quality in Caohai. These com-bined project managements can improve water quality of Caohai.