Study On Non-point Source Pollution Of Phosphorus And It's Spatial Distribution In Chaohu Basin

Now,the lake eutrophication situation is grim,it has become an important factor restricting China's economic and social sustainable development.In recent years Chaohu Basin has been showing serious eutrophication.The main reason of the eutrophication of Chaohu is the amount of phosphorus.The government carries out large amounts of money and engineering control of water eutrophication in Chaohu basin every year,although the basin's major point source pollution has been effectively controlled,but the eutrophication has not been eradicated.The related studies showed that the phosphorus pollution in Chaohu was mainly from non-point source pollution.But now,there is no clear and profound understanding of the number and distribution characteristics of the non-point source phosphorus pollution in the Chaohu Basin.To effectively control the amount of phosphorus discharged into the Chaohu water,One problem that urgently to address is to explore the number of non-point source phosphorus load in the Chaohu Basin and its distribution,then identify the heavy load area,and control it effectively.The related studies showed that the number of phosphorus discharge of soil erosion,livestock breeding system and residents consumption system was enormous and distributed widely.This study took the Chaohu Basin as the research object.Based on the classification of land use in Chaohu Basin,this study used the USLE equation to calculate particulate phosphorus and depict its distribution by GIS method;Then this study distributed livestock phosphorus load and human consumption of phosphorus load by the means of developed model.All these results provided the basic data for the development of environmental planning and Non-point source pollution control policy in Chaohu Basin.The details are as follows:1.From 1988 to 2012,Chaohu Watershed land use had been significantly changed,The construction land increased from 193.33 km2 to 1168.42 km2,frost land fell a lot in 1988-1998,then staye stable.2.In Chaohu basin,the area of micro erosion was 10817.64km2,accounted for 77.5%.The strong erosion of land above accounted for only 1.35%,but it contributed 28%erosion amount.3.In 2012,the total particulate phosphorus load of Chaohu Basin was 3092 t;but in 1988 it was 2378 t.Higher P concentrations located in southwest valley and eastern mountain areas and where were high intensity erosion areas,so the maximum phosphorus load occurs mostly here.Particulate phosphorus is one of the important sources of phosphorus input in Chaohu,accounting for 25%of total amount,which can not be ignored in governance of eutrophication.4.Around Chaohu plain area,the livestock phosphorus emissions was maximum.Lujiang,Feixi and Shucheng were heavy load areas,accounting for 75%of total livestock amount.5.In Chaohu Basin,the phosphorus load of unit area of construction has been in decline for thirty years.The county town areas were highest load.But the human consumption phosphorus load of the vast rural areas accounted for 50%of human consumption phosphorus load.