The return flow of farmland is usually of poor water quality;however,by properly using the self-purification capability of rivers and lakes it is possible to improve the water quality of return flow.In this paper,Yuehai Lake in Ningxia as a case study,by fully taking advantage of the landscape lake's purification capability we developed a lake hydrodynamic-water environment mathematical model and through numerical modelling experiment to simulate and quantitatively analyze the effect of the water system regulation/storage method on the degree of betterment of water quality of farmland return water.The experimental result showed that under working condition,through Yuehai Lake the concentrations of NH3-N,TN,and TP were reduced by 0.80 mg/L,1.06 mg/L,and 0.057 mg/L,respectively,while simulated scenarios revealed that by implementing water-system regulation/storage return water quality in spring and autumn could be improved from Class Ⅲ to Class Ⅱ,and in summer from Class N to Class Ⅱ;and hydrodynamic force exerted a certain effect on water quality improve-ment,in winter,with water quality control scenarios return water quality was improved from Class Ⅱ to Class Ⅰ,while in quantitative regulation scenarios from Class Ⅲ to Class Ⅱ.It is expected that the research could provide references for the utilization of agriculture waste water and the optimal water resource allocation of the Yellow River.
维普
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