极端降雨事件下滇池流域富磷区非点源磷素淋失过程及机理研究

Enhanced frequency and intensity of rainfall has become a significant environmental change in Lake Dianchi basin, leading to a great increase of into-lake phosphorus load. However, the mechanism of phosphorus loss under extreme rainfall conditions is still not well known. To identify, quantify and optimize key parameters in the hydrological and transport process of phosphorus loss from non-point sources under extreme rainfall conditions, the lower catchment of Chaihe river in southern Lake Dianchi basin is taken as a case study. Based on outdoor cell rainfall-runoff experiments, high frequency monitoring of hydrology and water quality, runoff segmentation with environmental isotope, and distributed phosphorus simulation, runoff segmentation and transport mechanism of phosphorus along with different components of runoff and sediment will be revealed. Main contents in this study include: runoff segmentation under extreme rainfall conditions; loss mechanism of phosphorus along with different components of runoff and sediment under extreme rainfall conditions; quantitative estimation of phosphorus export from non-point sources under various rainfall conditions. The study is intended to provide scientific support for water resources management and phosphorus controls under extreme rainfall conditions in Lake Dianchi basin.

滇池流域近年来极端降雨事件的频次和强度增加，导致外海南岸富磷区的非点源磷素入湖量较大，但极端降雨事件下非点源磷素淋过程失及机理的研究尚显不足。针对极端降雨条件下非点源磷素淋失的水文和迁移过程关键参数的识别、计算与优化这一科学问题和技术难点，本项目选择滇池流域南岸富磷区柴河中下游小流域作为研究区，综合运用野外坡面小区降雨径流试验，水文水质高频监测、环境同位素径流组分分割、流域分布式磷素迁移模拟等方法，揭示极端降雨事件下径流分割和磷素随不同径流路径和泥沙的输移机制，识别不同径流路径的水文过程和淋失过程的关键参数。主要研究内容包括：极端降雨事件下径流组分分割研究；极端降雨事件下非点源磷素随不同径流路径和泥沙淋失机制研究；不同降雨条件下流域非点源磷素输出通量的定量评估研究。研究成果可为制定滇池流域水资源综合管理措施和极端降雨条件下非点源磷素控制策略提供科学依据。

滇池流域近年来极端降雨事件的频次和强度增加，导致富磷区的非点源磷素入湖量较大，但极端降雨事件下非点源磷素淋过程失及机理的研究尚显不足。针对极端降雨条件下非点源磷素淋失的水文和迁移过程这一科学问题和技术难点，本项目选择滇池流域典型河流作为研究区，综合运用实验室内降雨径流试验，水文水质高频监测、流域分布式磷素迁移模拟等方法，揭示极端降雨事件下典型流域磷素输出通量与驱动机制，以及磷素释放流失特征。研究成果可为制定滇池流域水资源综合管理措施和极端降雨条件下非点源磷素控制策略提供科学依据。