Hydrology character of Poyang Lake and its influence on water quality

Base on the measurement data of water level and water quality at four typical hydrological stations of Poyang Lake in 2008,the proportion of non-point source pollution for nitrogen and organics were analyzed,the variation of water quality with the water level and water cycle was also discussed.The results showed that:(1) for the whole basin,the proportion of ammonia load from point sources and non-point sources were 34% and 66% respectively,while permanganate index load from non-point sources was account for 80% of the total,anther 20% was contributed by point sources load.(2) During the flood season,the ammonia and permanganate index at hydrological stations presented the same variation tendency,they both increased first and then decreased with the raising water level.(3) Mean ammonia nitrogen concentration in dry season and wet season were 0.49 and 0.28 mg/L respectively,ammonia pollution in dry season were higher than that in wet season;mean permanganate index in dry season and wet season were 2.33 and 2.66 mg/L respectively,which indicated that the organic pollution in wet season were slightly serious than in wet season.(4) The concentration of pollutant at hydrological stations was increased with raising water cycle.If the water cycle remain unchanged,the concentration of pollutant in outflow was negative related with lake storage capacity,the greater of lake storage capacity,the less of pollution was.