Risk Sources Analysis And Quality Protection Of Groundwater On Both Sides In The Middle Route Of The Main Canal In South-to-north Water Transfer Project

This study was an applied basic research on risk sources of the Main Canal of theMiddle Route Project, characteristics of groundwater pollution, and the delimitation ofwater conservation districts, served as theme for the groundwater quality protection ofthe Main Canal of the Middle Route Project in South-to-North Water Transfer and as ameans of the field survey, indoor experiment, and numerical simulation; the results werepresented as followings.（1） Determine existence of many risk resources on both sides of the Main Canal ofthe Middle Route Project in South-to-North Water Transfer through the field survey andanalyses; and built on this, a database of groundwater risk sources was constructed toachieve functions of the automated management for information editing, queries, andstatistical analyses.（2） A principal component analysis was used to analyze13pollutants inunderground water from the Jiaozuo’s section of the Main Canal of the Middle RouteProject, and results demonstrated that nine out of13pollutants were main pollutionfactors; the order of contribution to the pollution of underground water was nitrate, totaldissolved solid, sulphate, degree of hardness, hexavalent chrome, fluoride, nickel ion,ammonia n, and chloride.（3） Results from the study on pollution characteristics of the underground water nearthe furfural plant in Cixian county, Hebei province showed that total degree of hardnessin inorganic components, chloride ion, and dissolved total solid exceeded sanitarystandards of the water for living and drink （GB5749-2006）,1.79～2.53times,2.37～2.47times, and1.26～2.05times higher than their standards, respectively; halogenatedhydrocarbon and polycyclic aromatic hydrocarbon were primarily detectable organiccomponents, but both concentrations were under their sanitary standards.（4） Area of Dajia Zuo in Jiaozuo was located in an environment of highly alkalineand oxidizing, changing from Cr³⁺to Cr⁶⁺was easier; therefore, the pollution ofunderground water was appeared as Cr⁶⁺contamination in this area, and Cr⁶⁺ contamination in phreatic water became worse and worse.（5） Risk sources’ simulation conducted in the furfural plant of Cixian county, Hebeiprovince illustrated that underground water on the left bank of the Main Canal （in thewest） was inclined to pollute the water quality of the Main Canal; under no drainage orless drainage in the Main Canal underground water on the right bank （in the east） was notinclined to pollute the water quality of the Main Canal; for the site of the most west plantwall near the Fusheng Furfural Plant, certain risks existed when the maximum possiblewater-head of4m and the aquifer permeability coefficient of20m/d in the segment of thecanal, as well as continuous distribution of500m and range of influence of about180mfor the water supply and drainage.（6） Simulating results under different scenarios in the area of Dajia Zuodemonstrated①under no pump water, Cr⁶⁺pollution plume would arrive in the MainCanal of the Middle Route Project in South-to-North Water Transfer after20years ofmigration; after30years the concentration would be0.06mg/L when Cr⁶⁺pollutionplume could reach the Main Canal;②with pump water quantity of5300m3/d, hydraulicintercept and capture section effectively controlled the migration velocity of Cr⁶⁺pollution plume, and Cr⁶⁺pollution plume would be captured on the hydraulic interceptand capture section60years later and no longer could migrate along flow field forward.（7） In light of the purpose of the transmission of water for the Main Canal of theMiddle Route Project in South-to-North Water Transfer, water conservation districtsought to be delimited according to the water standard for the source of drinking water; ofwhich, water conservation districts should be delimited for the non-open channel andopen channel, respectively.