Current situation and countermeasures of prevention and control of non-point source pollution from farmlands in water source areas of the Middle Route of the South-to-North Water Diversion Project
Xin Xiaokang
Wang Chao
Liu Gen
Cheng Jinghua
Qin He
Chen Zhengyou
Xiao Xinzong
Abstract：In order to further clarify the sources of pollution in water source areas of the middle route of the South-to-North Water Diversion Project for water quality protection,a long series data from 2017 to 2023 was collected to access water quality of the Danjiangkou Reservoir and the incoming rivers.Methods of data collection,literature research and model calculation were adopted to estimate the composition of total nitrogen and total phosphorus pollution loads.Problems with control of non-point source pollution in water source areas of the middle route of the South-to-North Water Diversion Project were examined by empirical analysis,with proposal of measures and suggestions.The results show that the water quality of the Danjiangkou Reservoir is generally good,and meets the Class Ⅱ water quality(lake and reservoir water quality standard).However,during the flood season when water flow is big,the increase in total phosphorus concentration will result in a big number of the river sections that fail to meet the standard.The typical years when the Danjiangkou Reservoir achieved a normal water storage level of 170 meters were 2021 and 2023.At that time,water quality of the main inflow rivers such as Hanjiang and Danjiang was deteriorated from Class Ⅱ to Class Ⅲ(river water quality standard).Both in dry and wet years,non-point source pollution from farmland has become the dominant factor affecting the water quality of the Danjiangkou Reservoir,with total nitrogen contribution rates of 85.16%and 57.73%,and total phosphorus contribution rates of 77.74%and 57.17%,respectively.At present,the main challenges faced by control of non-point source pollution from farmlands in the water source areas include lacking of data on non-point source,unwillingness of farmers to reduce fertilizer and pesticide utilization,and difficulties to realize the value of ecological products.Therefore prevention and control of non-point source pollution from farmlands is urgent.Measures are proposed for establishing an integrated monitoring and early warning system of sky,space and earth,developing new-type and highly-efficient biological pesticides and fertilizers,creating a non-point source control system for ditch and pond water systems,and studying the mechanism for realizing the value of ecological products.
Keywords：the Middle Route of the South-to-North Water Diversion Projectwater source areanon-point source pollution of farmlandprevention and control strategy
Publication Date：2024-10-27
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：8( 81-88 )