雨后入湖溪流磷污染对西湖的影响及其对策

入湖径流是西湖磷的最主要污染源，尤其是暴雨后径流的磷污染最严重，梅雨（2001年）和台风雨后径流的磷净输入为1.77t，约占西湖全年磷总沉积量的42.5%。西湖流域内土壤表土的磷含量约是母土的两倍。西湖流域内土壤表土富磷和暴雨的冲刷和淋溶是导致雨后径流磷浓度提高的主要原因。提出了几种减小和消除径流磷污染的几种方案，通过分析比较，建渠排暴雨后径流水到钱塘江是比较彻底的消除径流磷污染的措施。

The effect of phosphorus of runoffs after heavy rains on the water quality in the West Lake and its countermeasures

During rain season such as plum rain (the year of 2001),quantity of input of phosphorus from the runoffs in the West Lake basin is about 1.77 tons, or 42.5% of total quantity of inlet of phosphorus in a year. Surface soils in the West Lake basin have accumulated phosphorus. Content of phosphorus in surface soils is about or more than twice of matrix's. The main reason for high concentration of phosphorus in runoffs is that surface soils in the West Lake basin have accumulated phosphorus and there are a lot of heavy rainfall in the West Lake basin. There are four countermeasures for dealing with nonpoint phosphorus pollution, among them diverting runoffs water into qiang dan river and protective reservoir receiving runoffs water are effective ones.;