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Water pollution in the drainage canals in the Hetao Plaint has been a serious problem affecting the water quality in the LakeWuliangsuhai,and consequently,threatens the water safety of the Yellow River.An effort was made to investigate the pollution features along the main drainage canal and in the LakeWuliangsuhai.The 5 main water pollution indicators of TN (Total Nitrogen),NH-N (Ammonia Nitrogen),T-P (Total Phosphorus),COD (Chemical Oxygen Depletion) and BOD (Biological Oxygen Depletion) were monitored along the MainDrainageCanal and in the LakeWuliangsuhai.Pollutant concentrations in the Canal and in the Lake were rated as "Heavily Polluted".Neither increasing nor decreasing trend in terms of the pollutant concentration was found along the Canal downstream Pollutant concentrations were high in the inlet area of the Lake,but decreased with the increasing distance from the inlet.Water quality was poor in the spring low water period and was improved in the Summer-Automn season when the water volume in the lake was high.